What a coincidence, I've been messing with connecting my MBP to various monitors and TVs lately.
I'm still on an Intel mac (15-inch, 2016) at the moment. I've been poking at different HDMI issues with it. I'm trying to game with it (using CrossOver to run Windows games on the MacOS desktop). I have been finding that I get different results, depending on which USB-C-to-HDMI adapter that I use. Usually it works, but under certain conditions and screen resolutions, depending on which adapter I use, the screen goes black and the monitor (or TV) says "no signal". Or, it works, but, there is some kind of intermittent CPU problem where my mouse response is jittery and the cursor bounces around the screen.
You should try to rule out whether the problem is truly HDCP, or some other funkiness with the adapter. Some adapters are thunderbolt-native devices and others are just USB-C devices. I think (not sure) that the latter require some kind of software driving to occur on the Mac side, causing additional CPU usage. I have been through several adapters and gotten different results with each of them, indicating that the Mac support for each one differs slightly:
- Plugable thunderbolt two-monitor adapter
(Amazon) - Certain resolutions cause a black screen "no signal", but, no CPU/mouse issues. If I can program the game to be one of the supported resolutions, this works great.
- Older Anker C-to-HDMI adapter
(Amazon) -
Works with all resolutions, but, CPU/mouse issues sometimes occur when using.
- Newer Anker C-to-HDMI adapter
(Amazon) - Certain resolutions cause a black screen "no signal", and also, I get CPU/mouse issues.
- Via a CalDigit TS4 docking station, Plugable active DisplayPort-to-HDMI adapter
(Amazon) - Certain resolutions cause a black screen "no signal", and also, I get CPU/mouse issues.
- Via a CalDigit TS4 docking station, Caldigit active DisplayPort-to-HDMI adapter
(Amazon) - Certain resolutions cause a black screen "no signal", and also, I get CPU/mouse issues.
So even without HDCP getting in the way, this stuff can be hard to get working right, and it may be dependent on which adapter you're using.
Footnote: I've heard that the M1/M2 macs can't drive dual monitors off of one thunderbolt cable. (My Intel mac can, no problem). True?