My officially first M.2 is Samsung 970 EVO PLUS, 1TB.
People told me few weeks... You have everything only need M.2, buy some 256GB version it's not expensive.
And I bought, but I keep tradition to stay with 1TB drives.
Example if I decide tomorrow to switch desktop for laptop and choose ASUS ROG 16GB not 32GB, with one HDD without SSD and NVMe M.2, i7 and GTX1080 price is 1500-1600 with SSD-M.2 and 32GB memory price is 2200-2300+... I don't plan to do that, but sometimes life simply force you. People travel, get job in other countries, etc and need to do something like that for first time. You will not find laptop with Samsung EVO 1TB SSD + Samsung EVO 1TB NVMe example for sure for some normal price.
And I have several years old CORSAIR SSD SATA III 128GB. He waste space actually and will serve as backup disk.
I want to avoid that in future and 1TB will be main size longer time.