Parlay is better in my opinion because you choose the matches yourself, while in slots you rely only on luck and nothing depends on you. Maybe such a win will go to one player out of thousands, but more often the winnings are much smaller. Parlays with high odds also win, and there are players who can repeat this more than once, but it is not for everyone and it is also difficult.
Your belief doesn’t change the reality that parlays are basically dependent on luck.
You can be confident with your picks, sure, but it’s hard to deny that the odds are stacked against us.
Just look at the chances per leg:
2-leg parlay = 24% chance
3-leg= 12%
4-leg = 6%
5-leg = 3%
…and so on. The more legs you add, the lower your chances get, eventually dropping below 1%.
At that point, it’s no longer about skill, you need extreme luck to hit a parlay, same as playing slots.