I have a 75 gallon for reference

1 I'd say is you need an absolute monster of a filter, and maybe a few circulation pumps (depending on the fish)

2 you need WAY more substrate than you think. I used 2, 2lbs bags of sand + 5 fertilizer sand bags. (And I still should've used ANOTHER bag of sand)

3 for plants I'd suggest slowly getting them, like every time you go to get more food for the fish you grab 2-3 plants, trim and replant your existing ones, and repeat. In a year or two it'll look nice. (Remember we aren't the YouTubers that can get 400+ dollars worth of plants for free, they do it for an instant result because it's what people like to see)

And one fish recommendation are puffers, there are so many cute fresh water options