FoundryVTT Do not consider the reMarkable or Boox Max. they are great devices; I have several, but an eInk device is not very capable. They do not have a very good GPU and ogften very low memory. The refresh rate is also not what you would expect. So yes, I can open FoundryVTT on my Boox Note or other Onyx readers, but I prefer to use a Samsung Tablet or my Thinkpad as otherwie the performance is abysmal.

If you do play solo or pen-paper replacement/tabletop roleplaying, an eInk would work. That is what I do with Obsidian and some of my campaigns.