So I just bought a physical copy for Switch because it's just dirt cheap new right now. I've never played a monster hunter game before but the Japanese setting really drew me in. Do people still play the base game online? Am I okay to mostly solo it?
There will be a large text dump at the start of the game to explain every little mechanic. I suggest you mostly ignore those for now, you can always read them later from the tutorials secion of your menu. Grab the weapon that seems the most interesting and start with Hinoa. Thats the start of the main "story" of the game, if you complete them all you can skip the first few levels of the hub quests.
Plenty still play, I have solo'd every monster up until the last 2 DLC, but if any are giving you trouble you can always host an online hunt, someone will most likely join.
I would recommend sword and shield, longsword, or dual blades as decent starter choices. Though if something else clicks, feel free to use that one. I started with charge blade, it was a hurdle but it is my favourite weapon.