5120x1440 is fewer pixels than 4K so 60Hz should be easily doable with HDMI or USB-C or DP.
There are a few DisplayPort 1.4 to HDMI 2.1 adapters available. I’m not sure if the chips can fit inside the Framework expansion card form factor.
- Realtek RTD2173 as used in the Club 3D CAC-1085 (and probably CAC-1586)
- Synaptics VMM6100 as used in the Cable Matters 201388.