Which hosting company do you use for the VPS? I am in the USA.
Despite it being easier to self-host XMPP and less expensive on resources, Matrix is more popular. Why?
The real reason Matrix is popular is because corporate and FOSS developers like the encrypted group chats for their internal use. (XMPP is NOT encrypted group chats). So then devs host a Matrix room to answer end-user questions, and having all these rooms encourages overall adoption.
The part that's not usually mentioned, is that only the devs usually use self-hosted Matrix servers, and the vast majority of the public uses Matrix.org which is on Cloudflare with Gmail verification.
In theory Matrix is decentralized, but in the real world, everyone gets Cloudflare metadata surveillance, and uses the same Element client.
Here's my core message:
Try to be Self-Sovereign with what you're doing.
If you're hosting a website, 1 core VPS for email, whatever. Then host your own XMPP/Matrix. XMPP uses so little resources, it's near free.
If a VPS is really not for you, even if you pay someone like me $100 to set it up:
https://simplifiedprivacy.com/email-cloud-combo/index.html
Then public SimpleX/Session servers are right for you. That's fine. This isn't about me trying to force you to use my favorite protocol. It's about you not using Cloudflare (and Protonmail seeing your metadata) and thinking you're "doing privacy".