I might be having something similar happen to me as well.

When I was doing the new trial (mostly its Extreme version) I feel a some discomfort but couldn’t tell exactly why.

Then I did M5S and M6S a bunch as tank last week and felt ok, although yesterday evening I played them with friends and I was RDM. After an hour I started getting bad headaches and had to ask for extra breaks. I’m suspecting that the flashing lights of M5S and the bright colours of M6S ended up being too much for me when I also had RDM’s big attacks happening, because I didn’t feel as much discomfort if I looked away from my screen during my burst windows, and I haven’t had this problem playing RDM in other content, or when doing M5S/M6S as GNB instead.

This has never happened to me before when playing this game, and I wasn’t sick yesterday and am feeling completely fine today. I started playing this game in 5.5 and started raiding in 6.2. However there are times if I’m playing other games, or am watching tv, or am at concerts, where I can have discomfort or headaches because of bright lights.

Next time if I’m in there M5S/M6S, if I’m playing RDM I’m going to turn my effects off and see if it helps. But it sucks having to use Limited effects for RDM because that turns almost everything off. In M6S’s add phase it’ll be hard to see if I aimed Resolution properly and hit all the targets I wanted to.

So I would really appreciate if the settings allowed for more customization to how certain effects are displayed. Both for boss effects and for our own jobs.