Is it possible to create access point from Raspberry Pi 3B+, without ethernet? I'd like to create access point like for example android hotspot, were you can start hotspot but you still can use internet on device as well. Do you have any idea how can I make it?
I think no, but I am not 100% sure. I think it is not possible because at any one time either you can join a hotspot or create one, but you can't receive and send. You can test it with an external Wi-Fi adapter so one can use as receiver and second one as transmitter or AP, as a Wi-Fi repeater does.