Ignoring that power levels are arbitrary and can fluctuate for plot reasons, constant eternal training would presumably lead to results surpassing the gods of the universe. There seems to be differing potentials, but we've never seen a hard cap on anyone's strength. If I were to fancy to put more thought into it than TTT, I would say that the power levels are relative to the Mortal Level of the universe, and more importantly, the relative power levels of the people around them. That's really the only way to explain why some characters stagnate (Future Gohan and Future Trunks) despite years of fighting.We have seen hard caps, but they just stop for plot reasons as well. Like Goku, Vegeta, Piccolo basically couldn't get any stronger during the Cell saga and it was made a point of contention that only Gohan could do it.
Doesn't take that long:
https://www.viz.com/shonenjump/chapters/dragon-ball-that-time--got-reincarnated-as-yamcha
Yamcha catches up to Goku, in just over a decade.
i read a small summary of that spin off which i know isn't authored by toriyama/toyotarou, if i remember correctly doesn't yamchahit a hard limit where's he's like uhhh im not useful anymoresometime in that series? i think he realizeshe's not enough for Cellor something, i did not read the actual manga so correct me if im wrong
I think hei seevoluntarily jobs because otherwise Vegeta never hooks up with Bulma which means there's no way to get Goku the heart medicine or some stupid shit like that