I feel you. For IM specifically, one thing you could do (if the IM platforms you want are supported) do is to set up a Synapse homeserver with bridges and then

I feel you. For IM specifically, one thing you could do (if the IM platforms you want are supported) do is to set up a Synapse homeserver with bridges and then you have everything (encrypted or unencrypted depending on config) in a SQL database. May not be worth the overhead depending on your hassle-tolerance if you're not interested in using matrix.org otherwise (I recommend it though). At least a lot of the annoying groundwork is already done. If you do hit some snags, bug reports and PRs are generally very much appreciated in the bridges projects.