Black screen after entering my login/password

Hello, originally I had Mojave OS, but finally decided to make an update and changed it to Sonoma. Every time after I turned it on and entered my login-password of a user it was showing a gray screen with not fully loaded menu and with no desktop picture.

Then I made it clean and installed Mojave back. Now the same problem - after I enter my login-password it shows me black screen till it won’t load the menu and desktop.

disk utility shown me no problems

don’t know how else can I explain it, but please, help me