First, verify that it supports 5120 x 1440. Most MacBook Airs don't (2019 doesn't). They support 5120 x 2880, but for some reason not this. That appears to be a software issue (according to some articles I've seen, Windows on the same macbook supports that).

I think any Mac that can support one of these will most certainly support two (look at Apple list of supported resolutions to verify; consider a 15-16 inch Macbook pro with non-intel graphics card).