For the Rank 31 speedrun, what is the easiest way to reset all your data when logged into an account? Do I have to create a new account for every run I attempt?

I tried playing while not logged in and clearing browser cookies and site data but I can't save any games doing that (slower for the speedrun).

Run it in an incognito tab

Run it in an incognito tab

I tried that on both Chrome and Firefox and the site still saves my data while logged in.

log out AND open an incognito tab

Is there any way to do this now that the only way to play this game is from the Ninja Kiwi Archive?

Yes, Open Ninja Kiwi Archive Menu -> Settings -> Clear Flash Storage -> Yes Close and reopen app