Upgrade to 20.04 from 18.04 GRUB menu hidden

I’m quite new to Ubuntu world and installed Ubuntu 18.04 (dual boot with Windows 10); all good, no problems, all works.

When upgraded to 20.04, i don’t see the GRUB menu, just 10 seconds of nothing, then Ubuntu 20.04 starts (with no other problem). I can’t choose what to start, which is really annoying.

I tried fixing GRUB with the installation LiveUSB, but could not.
I edited /etc/default/grub at the line by changing
GRUB_TIMEOUT_STYLE=”hidden” to add “menu” but that didn’t work.

I tried ESC during the 10 second blackout, and get the menu but nothing.

I then erased all of Ubuntu 20.04 and reinstalled 20.04 from the beginning, only to still get the same problem.

Then tryed the uBuntu 19.10 and again same problem.

So I got back to the 20.04 because i want really get it to work properly.

Does anyone knows how to fix it? Why i can’t get what to run with the 20.04?