The NAVITIME app is more reliable than Google Maps when it comes to transit planning. Plus, you can check the ticket prices including if you're using tourist passes (e.g. JR pass or local subway passes). Taxis are expensive af.
Tbh if you're not going in a big group, hotels are far more reliable than AirBnBs and their odd regulations.
Use coin laundry or washing machines in hotels instead of packing a lot of clothes.
I guess it might depend on which Akibahara store you're going to, but at least a good number of them when I went this year (IMO) are just too 'generic' with a lot of the floor space dedicated to just the most popular franchises, with uninspiring merch (e.g. tshirts, acrylic stands) that can easily be found online. Though this might also be cause I've been there a few years before and the magic has been lost.
Stuff in Nakano Broadway (where a large portion of the floorspace is dedicated to Mandarake's secondhand shops) are rarer and more diversified, and there's even a shop selling original animation cels of old anime (I was salivating over a Cardcaptor Sakura one which cost JPY500,000...). It's fun to browse through even when you're not buying anything. There's also the JOJO bar which is insanely cool.
I browsed r/JapanTravel a lot to look up tips and general recommendations.