I need help deauthorizing computers i no longer use

See the section If you need to deauthorize a computer that you don't have access to at the bottom of the linked article: Authorize or deauthorize your computer for iTunes Store purchases - Apple Support.

See the instructions below from Authorize or deauthorize your computer for iTunes Store purchases - Apple Support

(if you have a Mac computer running Catalina or later, use the Music app instead of the iTunes app; everything else is the same)

To deauthorize a computer that you don't have access to, you have to deauthorize all of your computers. Then authorize each computer that you have again. You can deauthorize all computers only once a year.

1. Open iTunes.
2. Choose Account > View My Account.
3. Sign in with your Apple ID and password. Forgot your Apple ID?
4. At the top of your Account Information page, go to the Apple ID Summary section.
5. Next to Computer Authorizations, click Deauthorize All.
6. Authorize each computer that you use again.