Is OMGF (Pro) compatible with WP Rocket?

Yes!

Since v3.18 WP Rocket has its own Self-host Google Fonts option. However, OMGF and OMGF Pro have proven to be much more reliable when it comes to local Google Fonts.

All you need to do is, make sure WP Rocket’s Self-host Google Fonts option is disabled.

To deactivate this feature, you can go to the Media tab, click on the Self-host Google Fonts locally checkbox and save changes.

OMGF Pro users also might want to disable WP Rocket’s Preload Fonts option and use OMGF Pro’s Smart Preload feature instead. It’s in the same section mentioned above, right above the Self-host Google Fonts locally option.