Circulation pump & circulation line not installed

We regularly took water...

From the circulation line? ;-) So: it may be that there is enough flow there as well. Depending on the length, bends, height, it is often the case that there is hardly any movement. Mainly because the resistance in the thicker main line is lower and the water mainly chooses that path.

Is it really sufficient to reconnect the last tap point to the boiler house? From the riser, there are still pipes leading to the fittings (also in the guest bathroom). These would still be dead ends and not loops if I now reestablish the connection to the boiler behind the last hot water tap point?

Branch lines are no longer allowed in Germany. Everything must be looped. There should therefore be no dead ends.

Attached are some photos from the time of the rough installations. This is the guest bathroom. The riser pipe goes up on the wall. To the left of it, the shower fittings are supplied. Isn't that a branch line to the Raindance fitting and to the washbasin/bathroom sink?

Is it the end at the washbasin? If yes, in my opinion, that is not correct. But I can only trust my plumber who once explained it to me. I haven't looked it up so far, so better check again!

I need to look through the photos I took. But I see a sting here.