Pph 8.0.30 Compatibility Issues

When activating the plugin on a server using PHP 8.0.30, I get an error:

The plugin generated 2 characters of?unexpected output?during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.

The plugin works still, but it breaks some of the ajax functions throughout the rest of the site, including the stats in the Admin Bar from Jetpack.