Lenovo P15 series would be example of laptops that have not gone crazy in light and thin direction, so it has m.2 slots for ssds, and sodimms for RAM as you'd expect, all accessible by undoing few screws and lifting the back cover: https://laptopmedia.com/highlights/inside-lenovo-thinkpad-p1...
Absolutely love my Thinkpad X1 for running linux; it's pretty much the same design but without the awful number pad. The fingerprint scanner even got support recently!
Or some random Dell laptop that seems pretty comparable https://laptopmedia.com/highlights/inside-dell-precision-15-...