iMac 21.5 4K Support?

[typical-sys]

I've been attempting to run Targetbridge (3.1.0) from a M2 Macbook Air to a 4K 21.5" 2019 iMac, with partial success. Both machines are on Sequoia 15.7.7.

The resolution settings on Targetbridge seem to be orientated towards the 27" 5K screen options, is it possible to have the 21.5" default of 2048 x 1152 as an option? Is the 21.5 4K iMac intended to be supported?

Secondly, I've been unable to get HiDPI to function, with the resolution displaying in the same blurred way as it does over wifi screen mirroring. I've tried two cables, an intel certified Thunderbolt 4 and a USB4/Thunderbolt 4 cable, as I understand both should meet the iMac's thunderbolt port capability, but I'm not passing 18.3 Gb/s on the cable test.

Any guidance appreciated, and big thanks for your work on this!

[ThomasWaldmann]

The iMac 2019 Intel supports TB3 and while that theoretically is 40Gb/s, practically, for a TCP network connection, it is ~20Gb/s. Thus, I think your cable/connection is fine.