What to do if your bathroom was painted with what appears to be interior paint instead of moisture resistant paint?

I just realized that my bathroom is painted with what appears to be just regular interior paint instead of using moisture resistant paint.

The only reason I am making this speculation is because the paint is a flat or matte finish instead of glossy or shiny that you'd typically see in a bathroom (and what I had in my prior place).

So, my question is whether I can apply something on top of the current paint to protect the bathroom from moisture.

The alternative is probably going to be repainting the entire bathroom (and I suppose, key areas in the kitchen too, I assume)?

Is there anything I could do in a cost-effective manner besides repainting?

If it matters, I do have an exhaust fan as well as a window that I can open in the bathroom after I am done showering.

I am attaching pictures what of what I mean by the flat vs glossy paint. The glossy paint was in my prior apartment. The flat paint is what I have currently.

https://imgur.com/a/aZB3a6P