Would you recommend a newer air or maybe a refurbished air from a few years ago? I'm completely unfamiliar with apple's lineup.

Any Intel based Air should work fine. You can even get ssd adapters to use regular nvme drives. I did that and got a 4x read, 2x write io boost.

Newer models are all arm based and Linux options are not as good on those AFAIK

Thanks 🙏 Thats wild. Like you replace the SSD inside with nvme?

Yes, exactly.

Something like these. It's just a mechanical adapter that makes the pinouts compatible. Apple had their own special drive connector because they are a garbage company, and wanted to overcharge for storage. China to the rescue. https://www.amazon.com/macbook-ssd-adapter/s?k=macbook+ssd+adapter