Can you provide more information about _issues_ ?
However, most compatability problems are caused by old plugins and/or theme(s) you’re using on your site.
Step 1, update plugins and themes
Step 2, read about jQuery updates in WordPress 5.5 and future versions
Updating jQuery version shipped with WordPress
Install a fix for jquery-migrate
https://www.ads-software.com/plugins/enable-jquery-migrate-helper/
Please note, this plugin provides only temporary solution until your theme/plugins are fixed.
Step 3, Gather debug information via notices in your dashboard
and browser developer tools (browser error console) for frontend warnings.
Figure what plugin/theme does make such warnings, contact plugin/theme author via support forum. Notify them that compatability update is needed for their plugin/theme, include warning notices.
Step 4, Wait for theme/plugin updates
Step 5, if you have updated problematic theme/plugins and dont see any warnings anymore, you can remove jquery-migrate fixing plugin.