"You can easily make a new account on Roblox to have a clean slate to play Meme Tycoon on."

Can I just make an account on a different browser

what do you mean

You can make a new account in an Incognito tab if you're using Chrome.

so like when i make a new account on a different browser (so lets say chrome cause my main is on explorer) and hit join game on it, will i join on my main? Will I log out of my main? And most importantly, will I join the game on my newly made account?

These are all of my concerns

Also why is the speedrun so long...

for one accounts aren't saved to browsers for two whatever account you're logged into when you hit play will be the one that joins the game