You don't have to replace the fixtures. You can replace the fluorescent bulbs with LED bulbs. Some require that you replace the ballast; some are plug-and-play. Bulbs with various color temperatures are available (some are color-selectable) and some are even dimmable. 1000bulbs is a source.

You can also get LED panels the size of your fixtures, for about $100.

much ado about nothing, bc of the ceiling itself, just change the bulbs. Until you are ready to tackle the ceiling its the best way to go.

I'd remove the vent cover, spray paint it white, and touch up the paint around the cover.

I see 2 lights out. So if just the tubes, then pretty cheap like $4ea to replace with fluorescents. If the ballast, which some are $30-$70, then it may be wise to convert to LED ($10-$25ea depending on direct wire or not). But you have to evaluate how many lights, whether to convert them all now, whether you stage a conversion over time, or are heading towards an eventual remodel anyway and new fixtures and ceiling then.

It's pretty simple to remove the ballast and change the wiring to accomodate LED bulbs. Worth doing if you are waiting awhile for the remodel. The light quality from the LED tubes is so much better than the flourescent light.