Keeps going into rest mode

Hi all, new here. Iv got an early ps5, when they first came out, which for the first 18months was vertical but is now horizontal.

Anyway I’m having a problem with it, when me and the wife are playing COD, split screen and on chat, it randomly turns off and goes into rest mode. We can play split screen and in a group of people fine but as soon as we put chat on aswel, it turns off. Going on chat is new to me

Iv had it in pieces, there is no fluff anywhere and the Liquid Metal had pooled towards one end. I spread it around again and reassembled it but still doing the same.

It gets warm but doesn’t really get too hot I dont think

The fan seems to work, but on my old ps4, I could hear the fan get noticeably louder the longer it had been on. The fan in this just seems to be the same from when first turned on, or at least I dont hear it get louder

Pictures are before I hoovered it and spread the metal

Has anyone got any ideas before I buy a new one?

Thanks