Now that everything works again, may be time for some tips:
1 - ALWAYS read announcements for the update. This will save you some headache. It is price to pay, to have the latest shiniest/rolling distro. You will have to be a little bit active with Manjaro. If you want less involvement, (but not the latest software) check out also MX Linux.
2 - DONT RUSH with the updates. Wait a day, let other first test the update for you, wait until some 100 users vote for the update. Check the update pool, (it is in first update post) and look at percentage of problems / no problems. If there are more problems than usually, wait longer with updating your system. And read what other users experienced and what was solution. Learn from other members problems, let others troubleshoot for you. I still didn't update. I'm first reading what happened. In this case, you troubleshoot this update for me, which I'm grateful for and thank you for In future you may want to be in my shoes, instead of leading the update research Oh and more there are problems, more is in your interest that you make some kind of a backup before the update. Just to be on a safe side. A month or so ago, I could not recover my system and I had to restore it from backup I created with clonezilla.
3 - In one of the earlier posts @papajoke posted the link to my guide, how to try to access the system when you can't boot properly into it. You now know how to access it from live USB, congratulations! Sometimes you may have a problem with graphical interface (GUI) but your system will otherwise boot OK. In that case you don't need to access to your system through live media, all you would need is simple switch top TTY. My suggestion is, that you are now getting ready for future potential problems that my happen. Check that link I mentioned and try step one few times and also step two. That way you will be ready for potential problem in the future. (step 3 you already mastered today) You really want to be familiar with first 3 steps.
Ah, and stop being angry, life is too short for this