I just got permanently banned from Reddit for literally nothing. No vitriolic comments. Nothing was modded. I have no other accounts.
The only thing I can think of is that I use a VPN. That’s it.
Edit: Come to think of it I did use a revanced modded client. Perhaps this was the reason.
Perhaps your VPN happened to associate you with an IP address from which other accounts do exist?
That’s my only guess outside of using a revanced client.