I can confirm that version 2.1.2 released in March 2024 works well with the Canon R6 Mark ii. Very easy to use, just connect a USB-A to the ASIAIR then a USB-C connected to the R6Mii. When you open the app, the R6 will show up as the only option for the main camera, select it! On the set up for your RX, set it up in B for bulb, make sure you’re set for raw images, not Raw+JPG.
What I found was that in the preview mode, you can only set up exposures to 30 seconds. But when you go to plan mode, you’ll be able to set up targets with exposures of however many seconds or minutes you want.