So I imagine it’s a Pi 4 8Gb? Did you install a 64-bit system on it?
Aha, that’s the point!!
The official Gladys image was a 32-bit image until now, so you can’t use the 8Gb of RAM. At best, you can use about 3GB.
But you’re lucky 
We just worked with @VonOx on an official 64-bit image. For now, we’re in the testing phase, but I tested it personally and it worked very well: