HDMI 2.1 is basically blocked by the HDMI forum:
"... This isn’t some unsolved mystery buried deep in kernel code. The issue sits with the HDMI Forum, which controls the HDMI 2.1 specification. To implement it fully, you need to agree to licensing terms that clash hard with open-source licenses like GPL. ..."
Source: https://www.makeuseof.com/hdmi-forum-is-holding-back-linux-a...
So I can perfectly imagine a small hardware vendor like Framework being unable to get support for this.
Perhaps DP is a better solution for your use-case?
Volkswagen tried to evolve to a more "touch" based HMI -that everybody hated- and is now touting it's abandoning that HMI as the largest redeeming factor of it's cars.
China is banning the ridiculous "innovations" on car handles and further "innovations" on steering wheels.
The Tesla software stack has few advantages: it's cheap and can be easily revised when the Beta-user discovers issues with it. So I have to pause and think to who's benefit it's made the way it is.
From an HMI perspective a Tesla is a nightmare, getting in and out one is constant question as to -why- these design choices were made. Especially after taking out "just doing things different" as a reason. A friend's first additions was loops to the physical door-releases so that passengers could actually get out should something happen and incapacitate the infuriating button-based door releases.
Luckily there is progress such as the recent Ferrari HMI that actually thinks about how the HMI will be used. The central screen even offers a palm-rest for when manipulating the screen. Integrating physical buttons and switches with the canvas of a screen is the logical way forward.
The car industry is soul-searching as we speak on what to do with technology and our interaction with it. But one thing is absolutely certain: whatever Tesla did is not the future.
I had a similar issue and wanted a "Google Photos" like product. So a web-interface with a time-based list and an phone-application that automatically back-ups.
I'm currently using Synology Moments/Photos which comes for free with a Synology NAS.
I've recently been on a trip with random strangers sailing on a boat and I could easily request the others' photos, import them in an album and share it with the rest of the group.
I'm struggling to find a better alternative that is workable and is almost set-and-forget.
So I can perfectly imagine a small hardware vendor like Framework being unable to get support for this. Perhaps DP is a better solution for your use-case?