Done! 
You can’t imagine how much I’m appreciating your suggestion … I’ve done a fresh installation of Budgie-raspi-23.10, accessed it from Ctrl-Alt-F5 terminal, installed raspi-config from mantic - universe (gldriver pretended it) then [dpkg -i]-ed (sorry for new verb 
) gldriver-test_0.15_all.deb previously downloaded, rebooted and …
So thanks, thanks and thanks again! 