Kaczorek wrote: I'm glad there is some progress on your side.
Regarding your questions...
1) Please try the main camera capture without connecting other cameras. Also make sure that you select proper camera i Ekos CCD tab when other cameras are connected.
2) You can go both ways i.e. connecting camera as INDI driver and use INDI CCD in PHD2 or connect camera directly in PHD2. The former should work, but it's not that effective because INDI is engaged in capturing and transferring images to PHD2, which in turn communicates with KStars/Ekos with guiding corrections. This approach makes sense for cameras that are not supported by PHD2 but are supported by INDI. Otherwise use direct PHD2 connection.

Thanks Kzczorek.
I can capture images and store them in the target directory, but once I execute my step 3) "Disconnect the guide camera (QHY5L-ii-m) in the INDI Control Panel.", which is essential for letting PHD2 to have the guide cam, it also disconnected the image transfer of the main camera. Re the screen dump below, clicking the "Yes" seems can't enable the image transfer. No preview showed on screen and no image are stored in the target directory.
I have also tried to disconnect and connect the main camera to see if the image transfer works, it doesn't! Any idea, many thanks!