i'm of buying a roku ultra 4k, but i need to make sure if it runs through usb input, bluray and dvd ISO files, bluray BDMV and mkv, could you tell me? I have several external drives with files in these formats. A hug to everyone!!
Go to Roku Ultra (https://www.roku.com/products/roku-ultra) and scroll down until you see audio & video supported format for USB port. I believe Roku supports most of the formats you asked for but except ISO.
I plan to ask Roku if they in the future support ISO format.