MacBook Air M1, can't display 4k@60Hz over HDMI

Hello!

I recently got the M1 MacBook Air and everything has worked fine so far. It connects to my 3440x1440@60Hz monitor just fine over USB-C, but unfortunately the display just doesn't deliver enough power to both drive the laptop and charge the battery at the same time. I got a USB-C adapter that handles everything over a single cable, but it didn't support 4k@60Hz, so I returned it and got a second adapter that does.

My issue is that I still can't output 3440x1440@60Hz, only 30Hz. I tried two different cables that are rated for 4k@60 (tried the cables with other devices, works great), then I connected the adapter to my TV instead of display to troubleshoot (the TV displayed 4k@60Hz fine using the same setup), then I tried connecting my work laptop (MacBook Pro i9) into the dock/monitor and it displayed 3440x1440@60Hz fine.

I'm really confused. Everything else I connect to the monitor gets the full 60Hz no matter what port I use or if I use the USB-C adapter. My M1 even gets 60Hz over USB-C, just not HDMI using the adapter.

Using cscreen command line utility I verified that both the i9 (over adapter/HDMI) and the M1 (over USB-C) lists the full range of resolutions and refresh rates, but the M1 over adapter/HDMI only list a subset that doesn't include 4k-resolutions over 30Hz.

I'm starting to wonder if the laptop somehow "remembers" that it couldn't display 3440x1440@60 on the previous adapter and is refusing to even try. Is there a way to solve this?