Can these doors or frames be painted? Or replaced?

Hello everyone,
We are considering replacing the doors since we are going to redo the floors and paint anyway. Now, due to the limited budget, we are thinking about leaving the doors in the basement as they are or possibly painting the door frames and only replacing the door panels. I suspect the surface is a plastic veneer (see photo), probably not wood. In the basement, inexpensive door panels from the hardware store would probably suffice for me. Upstairs, the renovation contractor Prüm suggested doors. My question is: How do these differ from, say, better hardware store doors?

Here are photos of the entire door

I think your door issue has already been addressed. I had recommended self-lamination. Otherwise, I would have left the basement as it is for now.

We have now at least removed the doors on the ground floor and will replace them. Now I am currently looking for what doors could be suitable. Most have long delivery times and no stock. I have looked at [Prüm] and [Herholz]. As a layman, I do not see any qualitative differences. All I want are plain white interior doors. I have read that CPL is generally more stable than white lacquer. Either would be fine for me. Now I stumbled upon [Kilsgaard]. These are mainly sold in [Baumkronen]. Are they inferior to the other manufacturers or are there qualitative differences? They are somewhat, though not significantly, cheaper in price. The advantage is that the stores more often have them in stock. Does anyone have experience with [Kilsgaard]?

Evil, evil spell "correction"?

Uh... yes ... so originally these doors might have been tree canopies... but I obviously mean hardware stores :)

Every manufacturer offers various qualities in their range. The manufacturer doesn't really matter.

Doors are available as chipboard, MDF, tubular chipboard, honeycomb board, or solid wood, as well as other versions. The manufacturer doesn't really matter. You should just know what kind of door you want.

Tubular chipboard is a very light door with less durability than a solid wood door. It is, of course, the cheapest option. It's always a matter of opinion. If you want cheap and nice doors and there are several, then I would buy them in Poland. But they don’t fit into German frames. Then it only works completely.

Otherwise, I get the doors from a specialized dealer. It is more expensive, but also good.

Kilsgaard are doors from Jeld Wen. They are sold under this name at Bauhaus. I equipped the entire ground floor with these doors last year and am very satisfied.