Check out onyx boox offerings. They have an 11inch tablet that works as e-reader, and also as external HDMI (with HDMI port in the tablet) screen that can be connected to any device.
tldw: it's not great for non-ereader tasks. the display is fine, but the tablet is hampered by slow hardware and bugs in its customized Android. using normal apps is challenging even with the compat tricks the OS gives you (e.g. disabling animations, "high contrast")
he mentions that Onyx also offers a non-tablet e-ink monitor, maybe that's better?
What would be non-e-reader tasks that I would want to have on an e-ink monitor? I have used mine to read books in all possible formats (including non-e-ink-aware android apps, with compat tricks), annotate, browse the web. All of that with great experience. What other things does one realistically wish to do on any e-ink display? I saw the video, but my reaction was perfectly summed up by one of the comments:
"What? It has terrible input lag? The framerate is like
5hz?! It's only in black and white??!
Man, my plans to make this my main 144hz HDR gaming
monitor have been crushed."
just, y'know, computing! sure i know i won't be watching videos, but anything else you'd do on a normal computer. because i like e-ink screens :)
i don't think the refresh rate comment is fair - he mentioned the lag when he demo'd writing in Google Docs, and just said you get used to it. but there's a difference between the screen being slow and the device being slow, no?