2 reps in reserve is fine and far less painful, but you need to go to actual failure often enough to know where failure is on each set. I’m nerdy enough to suggest rolling a 20 sided die for each set, and on a 1 take it to failure it’s not that complicated and keeps your predictions honest.

As I understand it taking a set near failure works reasonably anywhere between 5 to 30 reps, but 30 well controlled reps with good form * 3+ sets for each muscle group gets really boring.

Boring is subjective though. For some like me the ideal weight gives endorphins where as too much feels like cortisol. Too light is sort of nothing. So I aim for that "yeah I pushed something" feeling. Which isn't failure.