Had I played this move for Black #53 instead of the original, is there any chance that either of white’s two groups (circled in blue) would have survived if I went after them immediately, and if so, would it have in any way endangered my black group on the left (circled in red)?
I think your original move 53 wasn’t bad. It does give you an extra liberty. Playing a net at M5 lets white link up under your stones. A better followup to white’s response to your original move might be R6.
You could also just capture the N9 group directly. It’s the critical group. Killing those stones links your weak stones. The N6 group is unimportant.
Variations are in the chat.
After black M7, the group of 5 white stones can’t escape anymore and all the black groups are safe (unless you make a reading mistake). The remaining white stones in the area don’t have enough room for two eyes.
I would just play #53 somewhere else, for example at F17, and then respond quietly to any attempt from white to live in the lower right.