If your mainboard has onboard Nvidia or Intel graphic chipsets in addition to your discrete AMD RX 6600 XT, then removing those might not be advisable; and if not, leaving them installed does no harm as they would then not be used.
Anecdotal:- If you ever need to swap out your graphics card for another – for any reason at all – it’s likely convenient to keep them updated with the rest of the system.
To help ascertain whether they are needed, please provide your system information as described (below).
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, and formatted according to forum guidelines) will generate information useful for those wishing to help:
inxi --filter --verbosity=8
or the short form (preferred):
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.