This isn’t going to be a 20.04 ISO - Lubuntu and Ubuntu at large don’t support 32bit ISOs anymore, so it’s not a valid test.
On your 20.04 system can you get to the GRUB bootloader and get a list of what exactly is booting in the kernel of your system? Press and hold Shift when you start your system (AFTER the Dell logo, but BEFORE you are actually in Lubuntu, go to either “Other Lubuntu Versions” or “Other Linux Versions”, and boot to an Lubuntu / Ubuntu that uses 5.4.0 as the kernel version. See if that gets you back into your machine for now.
If it does, then run
sudo dpkg --get-selections | grep 'linux-image-' | grep '5.8.0' and include the output of this command here, so we can see what kernel versions are installed. If you’re on the 5.8.0 kernel (which it usually will now default you to for 20.04 installations because of the global enablement by default of the HWE kernel stack - basically backported kernels from later releases to *buntu 20.04), this is likely a regression caused by this kernel, and we’ll have to work through the process of filing a regression bug with the Ubuntu Kernel Team.