Hello, the synology website explains that their NAS are compatible with C2, see below.

Hyper Backup allows you to back up data to Synology's cloud service, Synology C2, a seamless solution that ensures data availability on the cloud for Synology NAS users. With different price points to choose from, you can access and restore your files on any browser while enjoying data security guaranteed by encryption technology.

As for lockups on the DS118, I've experienced those rare lockups indeed, after that I don't do daily restarts.

This product works with C2 (via the Hyper Backup application).

I manage Synology NAS for several people (privately, I'm talking about 5 devices) including 1 DS118 and I have never had any problem of this kind.

I follow all Synology updates (currently DSM 6.2.3-25426 Update 2) and my DS118 has not been rebooted for 35 day(s) 12 hour(s) 23 minute(s) 2 second(s) .... and the reboot in question was due to a "plug pull" by one of our children ;-)

Hello, no idea. I would recommend another product as the DS118 needs a daily reboot for it to work normally. It tends to lock up by itself, (tested on 2 different models).