Solasta as a platform for solo DnD?

Yes. Solasta is a faithful implementation of the 5e mechanics, with races and classes copied directly and sub-classes being OC to a large degree. There may be some stuff missing though, at a glance BG3 is more comprehensive in how many spells, items are there. The entire setting is also an original thing, we're NOT playing in Faerun there, the mosnters are different, the map is different, the lore is different and much smaller.

Compared to BG3 there's a lot less stories in Solasta. I've won the main campaign and the first DLC while trying to find as many subquests as possible and I don't think it would add up to 100 hours. But then there's the second dlc (which adds levels 12-16) and a myriad of fan content, so sky is the limit. Most quests are excuses to go out there and clear a dungeon or a swamp. Main plots are fairly on the rails and not too deep. The first DLC tries to be a bit more of a sandbox but in my playthrough the ending had a glaring contradiction in it so you see it's not too polished.

But boy, is the dungeon clearing pleasant. Solasta embraces the dungeon crawl and combat aspects of D&D - maps are very diverse, there's a good balance in number of different enemies (enough to not be boring, but not too many to lose track of how to deal with anyone), very granular difficulty settings. And the UI.

Coming from Solasta I can say BG3 has missed the mark in converting 5e to a computer game. Solasta is much cleaner and more accessible (bigger icons, better controller integration, clear movement in combat), multiplayer is easier to start, but is fairly unstable once the game is going. It's not a serious problem tho, desync doesn't kick out anyone from the game (just now everyone plays single at their machines), I can save and re-start the multi session with a save from the moment the server failed.

So if you want the tactical d&d with smooth multiplayer Solasta is the best thing there is. If you care for stories and roleplaying... not so much.

Solasta is a pretty fun story light DND game. I enjoyed it, but I never finished anything other than the original campaign. It's pretty generous with long rests and short rests, which kind of ruins dnd's precarious balance.

Personally I'm super tired of DND specifically. I'd love something like solasta but with a different system .

Solasta is an incredibly faithful recreation of the 5th edition rule set. And I absolutely love it. I've played the main campaign, all the DLC, and a fan made recreation of the temple of elemental evil.

The rule implementation is fairly strict, especially when compared with BG3. Can't be casting somatic component spells with something in your off hand. Your wizard spell book is something that you can accidentally sell (oops). Need to attune those magic items. But I find it all pretty fun and I felt like I actually learned more of the D&D rules.

The cutscenes and dialogue animations are... actually comically bad. But I like the idea behind the way scenes work. Basically you set your character's personality at the start of the game and then they automatically speak according to that. Some of dialogue is hilarious. Some of it is even internally hilarious.

But what really shines are the encounters and campaign design. The encounters are all very fun and well designed, there's a fair amount of verticality and environment interaction. Each encounter feels like it could plausibly be part of an an actual tabletop adventure. And the overall story also feels like something that your friend would come up for his homebrew world. It lacks the style and polish of BG3 but makes up for it with authenticity and heart.

Assist
Solasta is the closest I've ever felt to playing dungeons and dragons in a video game and I would highly recommend checking out the base game at least.

Me and a friend played it side by side, we thought it was an absolute blast.

Character creation is probably the most D&D aspect of the game. You get almost every race and class from the PHB, although Variant Human is unfortunately not there, and many of the subclasses are unique to Solasta. There are 12 backgrounds, most of which add side quests to the main story, and all of which give some benefit to the character. Stats are determined with either 4d6 drop lowest, or point buy, and there's an option for unlimited points. The game won't punish you for choosing 18s in every stat, but that's kinda boring. Character customization is kinda barebones. There are a few faces to pick from, like 30 hairstyles, and a wide color palette for skin and hair colors. Imagine Skyrim, but only preset faces.

Your background and personality traits determine your character's attitude, and what dialogue they say. The game is almost entirely voice acted, which is really nice.

From a D&D perspective, it takes the combat rules directly out of the SRD, and it plays explicitly RAW. No bending the rules for the new guy because he didn't know he couldn't make a bonus action attack after drinking a potion. No scooting someone's mini one more square over so they can do something cool.

Also worth noting, thanks to the strict adherence to the rules, rangers are actually viable!

There isn't a ton of roleplay, as your dialogue options are usually just "which character says something right now?" There are a few points throughout the campaigns where you have to make choices, and those choices do matter to an extent, but they don't make an impact on the overarching story. The main campaigns are pretty much linear, you just decide how to kill the enemies the game throws at you. The side campaign has a lot more in the way of role playing, because you do have to pick a faction to work with.

The game is a lot harder than typical D&D, thanks in part to the strict adherence to the rules, and in part to the fact that they have to balance out the insane amount of loot you get. Seriously, by the end of the second campaign, we were leaving +2 weapons and Winged Boots on the ground because we had that Tier 4 drip. Everyone had 24 for their main stat. The paladin had 28 AC, and a Cloak of Displacement. The sorcerer could fly, and had a +like 15 to hit. The rogue had two daggers each dealing 4d4 damage, so them sneak attacks were crisp. The cleric... could heal, when the party needed it.

All in all, it definitely scratched the D&D itch for me and my friend. I recommend buying the game and the DLCs.

Been playing Baldur's Gate 3. Don't get me wrong, I'm having a lot of fun and the game is polished and great. But I miss solasta for how close it is to 5e rules implementation and how clear and concise the mechanics are. (It draws predictive line of sight for you as you consider where to move). I'll be going back to solasta for more custom campaigns (and the UB Mod) when I'm done with BG3.