If you’re still using Discord, consider the wealth of alternatives:

Matrix is the federated option. Allows self-hosting with federation, has encryption (though it seems to have vulnerabilities - be mindful), supports both public and private rooms. Does not support voice or video.

Stoat, formerly Revolt, is a very close analog. It’s FOSS, and is self-hostable, but does not federate - users on a private instance will not be able to interact with users on the public one. Supports voice; video not yet supported (I don’t believe) but is on the roadmap.

Root is very close to Discord but is closed source. Supports voice and video.

Fluxer is another close analog. Supports voice and video (and has the highest quality streaming out of all of them). Has an optional Nitro-like subscription (cheaper than Nitro, offers more) to fund it. It’s FOSS and supports self-hosting.