My activity lists a lot of processes. Is it normal?
MacOS launches many processes to do all the jobs that it needs to do. The number of process "triggered by you" is a small proportion of the total.

In general, if there isn't a "problem" -- such as one process using up all your memory or CPU resources, or a general sluggishness -- then I would assume all is well. Your memory usage certainly seems to be well within acceptable limits. (Low, green memory pressure, little Swap.)

You do have a lot of mdworker_shared processes. Processes starting with "md" usually belong to Spotlight. Sometimes Spotlight can work hard, indexing your disk, and launching several processes to do this. You should let this continue.
The MTLCompilerService processes are Metal support services, used by apps that leverage Apple's Metal graphics framework.