If code is where you’d like to contribute, a lot of large projects label some non-critical and low-complexity fixes for known issues as “beginner contributions”. They should be relatively easy contributions, for folks with some background in code.
Of course, if you have spare cash flow, donate a fiver to your favorite open source project. It goes a long way.
If simply using it is the goal, check out f-droid for android, an alternative app store for open source apps, and look into open source replacements for your usual suite of apps. It feels good to use, and to know you’re keeping your own data yours.
I assume some instances have coordinated-attack prevention software that disables traffic from past offender IPs, and VPNs are a common way to centralize and anonymize data. Whether malicious in intent or not, a strike against your VPN server might cause a blockage.