Why are you constrained by the size? Typically the ceiling is fine behind these- the paint might need touch up but it looks like you are doing that already.

If it comes down to budget priorities, replace the two tubes with LED "tubes" that are designed to plug right in. Available at amazon and big box stores.

Agree, use this fixture with LED tubes to up your light quotient. Spend the cost of a new fixture on some LEDs under the upper cabinets.

there are plenty of videos on how to remove those.

you may have to skim coat or patch and paint, but it's not difficult.

http://www.create-enjoy.com/2017/03/how-to-replace-fluorescent-light-with-flush-mount.html

then you could install something like this

if you'd rather have something like track lighting

https://www.momendeavors.com/mini-kitchen-remodel/

https://www.younghouselove.com/lights-ceiling-action/

If you wanted to replace the fluorescent tubes with LED tubes there's a great article on how to do it here https://www.ledfirstchoice.co.uk/led-lighting-uk/how-to-replace-a-fluorescent-tube-with-an-led-batten/

Take that fixture down there probably is just some small screw holes and the electrical connection up there the get a nice LED tack light with 5 heads all 4000K bulbs and patch the small holes . BTW the pics Beth shows will in no way replace that fixture for lighting a whole kitchen and no Edison bulbs in a kitchen either