Please provide system information as described (below).
You stated that you removed phonon-qt5-gstreamer and phonon-qt5 (for whatever reason) and now you cannot install them again.
That’s perfectly understandable, as neither package exists in the official Manjaro repositories any longer. The same goes for libva-vdpau-driver.
These packages were dropped to the AUR because (being qt5-based) they are no longer required by any official packages (Note: they may still possibly be a dependency of some outdated software installed via the AUR).
There is a phonon-qt6 package which I suggest you install;
sudo pacman -S phonon-qt6
and possibly these as well, while you’re at it:
sudo pacman -S phonon-qt6-vlc vlc-plugins-all
From what I’ve managed to glean from the limited information provided, there seems to be a problem with your strategy for performing updates.
A notice similar to the following appeared in a recent Update Announcement under Known Issues and Solutions.
This hopefully spells it out a little more clearly:
I hope this is helpful.
Regards.
Welcome to the Manjaro community
As a new or infrequent forum user, please take some time to familiarise yourself with Forum requirements, and the many ways to use the forum to your benefit:
Update Announcements
The Update Announcements contain important information and a Known Issues and Solutions section that should generally be checked before posting a request for support.
System Information
While information from *-fetch type apps might be fine for someone wishing to buy your computer, for Support purposes it’s better to ask your system directly; 
Output of the inxi command with appropriate parameters will achieve this (naturally, formatted according to forum guidelines) and will generally be more useful for those wishing to help:
inxi --filter --verbosity=8
or the short form:
inxi -zv8c0
- inxi man pages (Arch Manual)
Be prepared to provide output from other commands whenever asked. It’s equally important to provide as much actionable information as possible in your first post, rather than simply indicating there is a problem.