In the last few days, in every game I played there's a warning sigh telling that the cloud could not be synched because of high load... and it will retry next time, but it always fails for "heavy load".

I checked that my machine had a full free network band, so the issue seems not on my end.

Is is something with Galaxy servers ?

Or something could be went wrong with maybe the cache of my client ?

Have you checked your anti-virus?maybe that is causing the issue.

he is prob playing punk in which case yes its their server not his machine

I'm don't have Cyperpunk so all the server issues people speaks about are not my case, the cloud saves are on "heavy load" for every game I have installed, even the smaller ones.

Only cloud saves are not working here, everything else like updates/downloads, achievements, tags are synched ok.

I had a look at the webcache and the log files, and I have maybe and idea on what could have happened here...

One day I changed the system date while Galaxy was open, it was doing nothing, it was just open, but after that change, I suddenly saw a lot of traffic on the network...
A lot of addresses were contacted by Galaxy services at an extreme speed... Facebook (that I don't even use), and a lot of Cloud flare sites.

I tried to close Galaxy, but while it was still responsive, it didn't wanted to close and continued to send a lot of stuff to the internet.
I had to terminate it, twice.

It's after that day that my cloud saves are not synched anymore...

I wonder if a wrong date came to the server making impossible some kind of check...

Anyway this is ALWAYS reproducible, just leave Galaxy open, put your date some months/days forward then put it back again, and have a fun experience looking at how Galaxy will behave.

I also tried to delete the webcache folder, but the cloud save issue persisted anyway.

yes a wrong date does fuck network sync... thats just general networking and nothing to do with Gog or galaxy