> Dendrite is kind of deprecated as a homeserver these days, at least it doesn't seem to be the main focus of development and most recent commits are mere dependency bumps. Years ago, when the server was set up, choosing Dendrite seemed like a good decision, because it was easier to deploy and maintain than Synapse and there was a promise for a bright future for the first 2nd generation homeserver implementation. Unfortunately, migrating between Matrix homeserver implementations remains a problem with no satisfying solution, so we're kind of stuck on slowly rotting foundations.
Dendrite may or may not have been a good choice for a Matrix homeserver at the time the decision to start it was made, years ago. But the real problem, as the blog post points out, is that there is no good way to change that decision. Migrating to a new homeserver implementation is equivalent to destroying the old server and creating a new one from scratch - which also has the implication that any user whose account was on the old server loses that account and has to create a new one, because Matrix user accounts are tied to some homeserver (a bad design decision, I think). Tying system identity to someone else's server - and that server's domain name - is the cardinal sin of federated identity systems, the ActivityPub ecosystem has exactly the same problem.
That is also an unfortunate design on Matrix' part. I had no problem migrating data when changing from ejabberd to Prosody. Because they are open source, so it's not really a problem to export to ad-hoc text and import again.
But Matrix closely follows proprietary products in its design, and the database is treated like some internal affair that you are not to meddle in. You'd have to reverse engineer the data format from source code, which is not practical for hobbyists.