ᐅ Appropriate Lighting

Hello,
I have not yet found a suitable ceiling light for my bathroom. The problem is that this is a prefabricated house and there is insulation material in the ceiling.
Ideally, I would like to use small, flat halogen recessed spotlights, but these get hot. Maybe there are some that come enclosed in a housing. Does anyone have any knowledge about this, or how have you solved this problem?
Regards

Well, how should I put it...? It’s best to plan something like this in advance.

For your issue, there are heat protection spacers available for hollow core slabs. However, it will probably be quite a challenge to embed the associated transformer in the insulation layer from below in a way that allows inspection and is fire-safe.

To minimize heat generation, you can nowadays also use LEDs effectively; just make sure to check the lumen output and the beam angle of the spotlights.

I was not able to plan in advance because this is a renovation. However, I have now realized that I can access it from above (upper floor). I have read that there are Fermacell boxes for thermal insulation, but I don’t know where to source or buy them.

It's best to look around in furniture stores or online shops (on Amazon, etc., etc.). Fortunately, tastes vary, so no one can give you exact recommendations.