If you already reinstalled Ubuntu a few times, then I guess you don't need to upgrade it. You should make a fresh 19.04 installation instead, which is safer than an upgrade.
After fresh installation you should also change /etc/default/grub options, to see more messages and errors on your script while booting the system.
Please edit /etc/default/grub and remove quiet splash flags from GRUB_CMDLINE_LINUX_DEFAULT.
sudo editor /etc/default/grub
Then repleace:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
with:
GRUB_CMDLINE_LINUX_DEFAULT=""
and update grub with:
sudo update-grub2
Then when you're stuck you can take a picture of your screen with a smartphone, upload it to i.e. imgur.com and share it in your question, if it shows any errors.
Another thing you may want to try is to use nomodeset option for safe graphics option.
However as I said it's better to remove quiet splash options, so you can see logs during boot, that may help resolving the problem.
As @pomsky suggested, the issue was with the GNOME extensions. In this case, Desktop icons. Once I remove it, all was fine.
Thank you! :)
Best Answer
As of April 2019, there is no plan to deprecate any of them.
The most likely to survive over the long term is GNOME (plain GNOME).