I haven’t experienced it being slow. that might depend on the client you’re using. fortunately, there are a few to choose from.

it’s… different and takes some getting used to. it also depends on which client you choose to use.

get started here by choosing a matrix client: https://matrix.org/ecosystem/clients/

Matrix is a federated alternative to Discord that is both open source and highly concerned with user privacy. It’s also very popular here on Lemmy, and a lot of communities here use it.