How much crunch is too much crunch for you when playing a TTRPG like D&D or another system?

It's really hard to say. I definitely enjoy things that are interwoven but there are things that are ahurdel for me cause too much means I forget there are options. I'm playing ptu right now, which i love, but the fact that we need to use spreadsheets means I often forget abilities or somethings

It depends on where the rules are, whether they serve to reinforce the fiction, and whether they present the players with meaningful and interesting choices to make.

My metric for crunch has always been how often we need to reference the rulebook during play. That signals to me that the rules are becoming too much of a burden on the brain. It's, of course, subjective to each table though.

Like dakka, no such thing as too much (if it's done right). Optional rules to make a system crunchy are what I like, that way players can more readily tailor the game to their table (if that makes sense).

There definitely comes a point where the rules are no longer servicing the game, but getting in the way of it. Unfortunately it's sometimes hard to determine exactly where that line is drawn.