Is it possible to be station for 2 WLANs the same way it’s possible to be AP for two WLANs using virtualAPs?
Yes!
Please explain … usual device with single radio, how can it become station of two distinct APs transmitting on different channels?
It can’t if different channels
That’s worrysome. I asked since I wanted to connect car equipment (each such accessory as dash cam or OBD2 dongle hosts own AP for management) using LtAP mini LTE which only has one wifi card. I strongly doubt those devices allow to choose channel. Even more so that they all will use the same one.