I think it should be doable to use relayers for a lot of this stuff, similar to other services in the space. Basically you should be able to keep a lot of information private, but have some other party act as a relayer to pay for gas costs / fees etc. Then the problem is more one for the platform in terms of how it values its users.
If this is a strong need from some specific platform, we can sketch out what this might look like for e.g. RLN.