Raspberry Pi 5 support for Manjaro when?

As far as I can tell, and as @Sam_Fisher suggests, the support already exists, though nothing is offered in the repos at present. I don’t know how soon that might change.

Then I suppose you’re out of luck for the time being; but keep an eye open for breaking news.

As a new forum user, please take some time to familiarise yourself with Forum requirements; in particular, the many ways to use the forum to your benefit:

General:

The Update Announcements contain a Known Issues and Solutions section and should generally be checked before posting a request for support.

Output of the following command (formatted according to forum requirements) is often useful for those wishing to help:

inxi --admin --verbosity=8 --filter --no-host --width

Be prepared to provide more information and outputs from other commands when asked.

Regards.