Ok. Some news. I got a new EBB2209_RP2040 board and replaced the old one. And this didn’t help - the first print failed on the 40th layer.
Then I decided to add a capacitor to the ebb power line (I found only a big 470mkf-100v so I soldered it to power input contacts and it seems to me this helps - I printed 1.5hour part and then 2hour parts set.
So I think the cause is a voltage drop on power wires because of the toolhead payload: 70W heater block, 3xfan, pt1000 with max 31865, 3 bright leds and extruder drive (650ma). There is only one large capacitor on the ebb board - 100mkf-35v and it looks like it is too small for this load.
