> I mean like same as Ubuntu on an x86 laptop for general work.

I would say no, but then again, I would also not recommend using any type of container for that type of work either.

I use Container on macOS to build containers for things like Claude Code, Node.js, Java, etc.. You know, software I want no where near my host OS. I mount a directory in the container, if needed, and it's smooth sailing.

I do believe Container allows for one to run x86 containers with Rosetta, but I also know once you enable Rosetta, it's easier to reinstall your OS than to uninstall. I like to keep things tidy, so I will not go down this path.

> ext4-formatted SD card in my MacBook's internal slot

I would not use Container nor any other containerization tool for this task regardless of whether it is possible or not. I would be surprised if any VM client would be able to get this working too, but I've been out of the VM world for a bit.

It's also worth mentioning that come macOS 28, Rosetta will be dead and gone except for a select set of video games. That version of Rosetta will essentially be stripped down to the point of working just enough for those games and nothing more. So, I would not get too attached to the idea of running x86 binaries on macOS for too much longer.

I believe there may be some tools that can read ext4 on macOS, but UTM not reading from the host's SD Card is unsurprising. I have never used UTM, but I would imagine it would not have the capability to pass the SD reader through, but I could be entirely wrong.

I'd seriously recommend buying the cheapest burner Chromebook, x86 machine, VPS, or whatever you need if you think running x86 binaries and reading/writing to/from ext4 formatted storage will be in your future. You could maybe try an external USB SD reader, but I cannot comment if that would work either.