Oh, these plants are outdoor bonsai, these trees are perfectly accustomed to this climate (thick snow, -30C, some sunless days, etc) and totally do not tolerate indoor tropics.
I tried transplanting some local trees in the fall, as textbooks say, and they perished pathetically. The best time must be some other time. I suppose the best time should be early spring when roots did not wake up enough, but then I might need to break ice. Then now is fast growth slowdown moment, I suppose it must be the next best bet. I'm doing one at a time now!
I'm too afraid of machines messing up in this. First time I used ChatGPT it literally tried to kill me with an explosion (chemical procedure description done obviously wrong and dangerous; fortunately I asked about something I wrote myself), and with mushroom id it's even simpler than with chemistry.