Hi there @SiNae P. - thanks for reaching out to us.
As Karina mentions in the thread, upgrading from a Plus to a Professional shouldn't affect the version history of the files.
However, if you upgrade to a Business team, you'd adopt the version history offered by the team itself.
If you don't want your account's existing version history to be affected, would creating a new account to join the team be an option for you?
Give me a nudge whenever you have the chance to check this out. Cheers!