@TakoR I only recently made the move to focal (RC 2024-W03) and saw the same problem of hotspot only working with no password.
Some research revealed that Volla devices also had a similar problem that has been solved by adding a file in Networkmanager configuration.
The same fix (detailed below) works also for the Xperia X. You will need to reapply it at each upgrade of the OS until it is merged in the device tree, if ever.
1-From a computer open a terminal session on your phone using either "adb shell" or ssh. Alternatively you can do it in terminal app on the phone itself, but it is very cumbersome.
2-make the image writable (until reboot) :
sudo mount -o remount,rw /
3-create the new file with appropriate content:
cat << EOF > /etc/NetworkManager/conf.d/fix-ap-with-password.conf
[main]
wifi-wpa-psk-pmf-no-optional-ap=yes
EOF
4-reboot the phone
5- my (linux) laptop could still not pair with the hotspot at that point. So I deleted the failed wifi hotspot config on the laptop and also edited the hoptspot config on the phone, changing the password and rebooted the phone again. After that, the laptop could connect the hotspot with password. I guess that not all of these last steps are needed.
Besides that issue and other minor quirks, I am very pleased with the OS upgrade. I just changed the channel, and upgraded as I had done before for the xenial upgrade. After that, I upgraded all apps. The new version has about a doubled battery life (for my rather lite use case, at least) compared to xenial and it solved the bug which made the camera app record half-green pictures about 1/3 of the time.