Starting in early March, the platform will place every account into a default “teen-appropriate” experience unless it has proof that users are adults.
The move has brought widespread criticism from Discord users, who are citing privacy and security concerns following a recent breach of a third-party vendor that ended up exposing around 70,000 government ID images used to verify the age of Discord users.
Setting up Matrix/Synapse was extremely easy and done in a day. The self hosting part is not that hard and I would say migrating users would be the majority of your time. Plenty of VPSs online make obtaining infrastructure very easy.