Sonoff cloud-connected devices becomes unavailable every two minutes

Hi everyone. I have some sonoff devices connected to home assistant through Sonoff LAN integration. Some of them are locally connected, and they work flawlessly. I also have two other networks (away from home) where I have a 4g modem router and some sonoff in each one.
These are cloud connected to my home assistant at home.
Everything works fine, except that all my cloud-connected devices keep becoming unavailable for a couple of seconds.
I don’t think it’s a network problem, since they are always on in the ewelink app.
I would have no problem with this situation, but my logbook is quite useless since it’s always full of “xxx has become unavailable” “xxx turned on/off” and, most importantly, I can’t have reliable automations.

Do you have any suggestion? Thank you!