I am curious if the resynthesizer / heal-selection plugins work with Gimp 2.99.14 or if there are plans to integrate the plugins directly with Gimp 3.0?
I think your best bet is to use the equivalent G’MIC tool. Changes my workflow a bit but still usable. Unfortunately 2.99.12 broke the G’MIC QT plugin. G’MIC still works as a QT app standalone. Certainly not optimal.
G’MIC are aware of this, a deprecated routine, and that the plugin requires fixing, but last I looked there is no time-to-fix.
You may find this of some help: https://discuss.pixls.us/t/resynthizer-plugin/32455