I have been having similar issues, found this topic in forum and decided to add it here. My issue is on a 2 core machine, with one fullscreen application using usually around 50 percent of the CPU. When I connect remotely, Cloudberry Remote Assistant starts taking about 40-50 percent too and then any remote work is very difficult. It seems it comes and goes in bursts, usually couple seconds long where it completely hangs.
My idea was, that maybe the fullscreen app (industrial machine interface) is refreshing its screen too often and then Cloudberry is having problems compressing the image into data stream, even though the screen content is rather stationary and mostly refreshes some numbers. This is just a guess though.
If any forum admins are reading this, my diag log had number 149330 and I opened a ticket 252598, but I have only freeware account.