Interesting, I wonder why mine slowed down so much then. From what I remember it was after an OS upgrade, it was my first time trying a mac, and I ended up being disappointed and going back to linux, but I also didn't do a deep dive into figuring out the reasons for it.

I believe the 2011 era MacBook Air (EveryMac.com confirms only the 11”) had an entry level 2GB RAM variant. That one probably got pretty painful after just a couple OS updates.