The realm that I've been playing on with friends since 1.15.5, has been having awful lag since 1.16. It started with not being able to connect to the realm (Which eventually got fixed) and then turned into lag for all people playing on the server. I've tried all of the tips from the Minecraft Help Center regarding Minecraft Realms server issues, but none of them have worked. This isn't a client-side issue either, everyone else on the realm either cant get in, or have lag as well.