After some time I've bought a thermometer which can stand inside the stove's oven (
), and now tried also a leavening basket, a proper bread pot in clay (and its lid), and a new flour (Petra 1111).
Ps: the lid has three holes for the steam.
Well, still not the alveoli I'd like, and also a little burnt on the bottom, but not too appalling.
https://imgur.com/a/SpLQTTR