How do I get WiFi and phone service, technology in the basement

It also works completely without mesh and without controllers. You just have to ensure that the APs reject connections below a certain threshold. With good APs, this can be configured. The fact that this is often marketed as a "mesh feature" is rather confusing, as meshing actually aims at something different. In my experience, this works so-so with multiple Fritzboxes (over cable), but at least with the AVM mesh you can simplify the configuration of multiple APs.

Does anyone actually have experience with the Mikrotik Access Points? I want to buy two AccessPoints in the next few days. Even though I like to recommend the Ubiquity devices, they are personally not usable for me because of the cloud and controller hassle.

Yes. But they are not for laymen.

Even though I like to recommend the Ubiquity devices sometimes, they are not usable for me personally because of the cloud and controller hassle.

What do you mean by cloud and controller hassle?

I do not want to buy and install extra controllers in the network, use smartphone apps for setup, or any other paternalism (Chrome instead of Firefox is often mentioned online. No idea if that is still current). I expect to be able to log into the AccessPoints with any browser, just like with the Fritzbox, and configure everything there.

You can do that with Mikrotik, and really everything, with each router/access point able to function as a controller. As I said: It's not entirely trivial, but very powerful.