Strange visual effects with Gnome

[Richmond <dnomhcir@gmx.com>]

I installed Debian 12 on a laptop. I found that when the mouse was moved
up to the top menu bar it disappeared. If I managed to click on the menu
the mouse was invisible over the menu too. Also I noticed the letter A
from activities was missing.

You will forgive me I hope for installing OpenSUSE 15.5, but I still see
some problems with fonts although the mouse is always visible.

Hardware Class: graphics card
  Model: "ATI RV515/M54 [Mobility Radeon X1400]"
  Vendor: pci 0x1002 "ATI Technologies Inc"
  Device: pci 0x7145 "RV515/M54 [Mobility Radeon X1400]"
  SubVendor: pci 0x1028 "Dell"
  SubDevice: pci 0x2002 
  Driver: "radeon"
  Driver Modules: "radeon"

  vendor_id     : GenuineIntel
  cpu family    : 6
  model         : 15
  model name    : Intel(R) Core(TM)2 CPU         T5600  @ 1.83GHz

It's a Dell Inspiron 9400.

What can I do? I would install Debian 11 or 10 if I thought it would
improve the situation but I am not sure where the problem lies.