Well XGA is less pixels overall comapred to 720x1280, so from a technical aspect I would imagine it is possible. However, I couldn’t find any examples of other’s using XGA resolution on the Colibri i.MX8X.
So, tentatively I want to say “yes it should be possible”, but let me see if I can find additional examples or confirmation as well.
I was able to have someone try XGA resolution on the Colibri i.MX8X. A quick tests shows that it seems to work alright enough. But of course you should verify with your own specific display to be sure.