I was that way for the longest time. I was more than content with my 4 core 8 thread 4th Gen. i7 laptop. I only upgraded to an 11th Gen. i9 system because I wanted to play some games on the go.
But after I upgraded to that system I started to do so much more, and all at once. Mostly because I actually could, and the old system would cry in pain long before then. But Mid last year I finally broke and bought a 13th Gen. i9 system to replace it and man do I flog the shit out of this computer. Just having the spare power lying around made me want to do more and more with it.
The 4090 FE was doable in larger systems.
But I really doubt a 5090 would fit in anything considered SFF. Even stretching the definition to the max.Apparently the 5090 is the same length as the 4090, but only two slots. Maybe it’s taller but it’s hard to tell. That siad cooling the rest of your system will be much more of an issue with almost 600 watts getting blown around in there.