jimsi

I think that providing API to be used by standalone clients is far more better approach

I would recommend to use borgbackup - it is very convenient for security (it provides very flexible encryption options with safe defaults) and efficiency (deduplication)

I can't remember any recent good news about 0click mitigation

I use KeePassDX on Android and KeePassXC on a laptop, and they are synced with Syncthing. I have no issues with this setup

This might be a way better solution in terms of performance, but I cannot imagine way to run more complicated stuff rather only blocking IP in the firewall using iptables

My OpenSSH is located on a non standard port, 22/tcp is going to the endlessh honeypot.

How did you discover this? Anyway thanks for additional information

I have asked Cloudflare about this traffic, but support says "Cloudflare helps protect sites, and accelerate them. We do not attack sites, and our network can't be used to generate attack traffic." They deny any malicious outgoing traffic, but after I have provided pcap dump they just ignoring me and do not reply anything. Very odd behaviour for researchers.