The response in that Xiaomi.eu thread has seriously damaged the trust I had in the xiaomi.eu ROM. I've heard good stories about the ROM but if the community, even including a developer respond, like that to an issue like that, I don't think I can trust the website anymore, so I've blacklisted it in my pihole.
I believe custom ROMs published by what comes down to "a guy in a forum thread" are nice for proof-of-concept stuff, but should be considered insecure. Many of these ROMs disable security measures like selinux because these measures make it harder to get Android running correctly on proprietary hardware, removing one of the best security mechanisms the Android sandbox has for the developer's convenience.
I'll never recommend anything other than established brands like Lineage, /e/ or one of the security-focused ROMs to anyone. I mistakenly thought xiaomi.eu was one of the good ones, but it clearly isn't.
Do you have any other sources on popular ROMs to avoid?