CUBASE 10 pro problems with very high CPU values

Hello everybody.
For two months I have not been able to work with Cubase projects anymore, because after open one, the Cubase CPU spikes at 400/500%, with consequent interruptions and typical problems.

I work with a Macbook Pro15 ver.2018 (I7,16gb ram, 500gb HD) with SK Audio Scarlett 212. The software I use is basically Cubase 10 pro, Komplete12 and Keyscape.

After trying everything without success (freezing the tracks, buffering sk audio at 1024 at the limit of bearable latency, increasing the hd free space to 160gb) I decided to reset the pc and reinstall everything, with the foresight to load for Komplete12 only the VSTs that i use (about 50%), dedicating an external SSD to archiving projects. However, even though I now have a system HD with 300gb availables, the problem still occurred. In addition, the reinstalled Cubase cannot read the old projects saved on the external hd (in the project opening phase, after having addressed the Cubase to the external HD, the Cubase disappears from my view and I can no longer understand where did it go !!!)

In any case, I would need specific advice, because I am afraid that I will not get out easily. In case I could also visit a specialized center (I don’t know of any).

I would not like to discover that my macbook’s cpu / ram are already insufficient, with the impossibility of making any upgrades (see ram and hd pasted by Apple).

Thank you all.