I already own a switch would you recommend getting BFN on it for speedrunning

Do you have to buy nintendo online for each new account on the switch version Also is it fast to make new accounts on switch (it takes a while on playstation)

So I got another playstation account that can go online to use for speedrunning. I did one run in town center plants and then wanted to do another so I deleted all bfn save data on that account (even the backup). How ever when I open the game again all the data is still there. any help would be appreciated. :)

I am wondering how to start a new game in town center plants on ps4 without buying ps+ for another account or deleting my main account data.