How to help FOSS devs:
If you're happy, let them know! Often most of the feedback software developers and admins get is complaints about bugs. Happy feedback motivates.
If you're unhappy, file friendly bug reports and be patient.
Some have a Patreon, where money can be donated. That reduces stress and frees up more time to focus on development.
There is also always code that needs writing or messages that need translating or documentation that needs writing.