No m.2. I was overall okay with the speed, it just wasn't completely keeping up. The way I see it, if I could've plopped out the CPU and swapped for something a few years newer, like 2017 or so, I'd probably have been much less inclined to build a new computer altogether.
I don't like switching tech much. It's such a hassle. I kept my OnePlus One around until 2020, at which point I replaced it with a second-hand iPhone XS because Apple supports their phones forever by phone standards. I work as a software dev, so I already spend 8 hours of my day mucking about with tech, it's not something I'm overly keen on doing in my off hours.
Thus far I'm really enjoying m.2, it's a lot smoother than running cables and stuff for a SATA drive. I have a few SATA ports I believe but I still have a m.2 slot open, so we'll see! I think I'm more keen on getting a NAS for storage at this point.