You might not be aware, but completing side objectives is significantly harder after completing the main objective. Completing the main objective increases the enemy spawn rate by more than 4x.

For this reason, I always ping side objectives, as well as enemy spawns I want to kill, prior to the last main objective. Once the main objective is done, I almost always bee-line straight to extract.

With that being said, I also always make it a point to communicate what I'm doing. Ignoring comms is kind of a dick move, in my opinion, but I try not to judge in case English isn't someone's primary language or if there are other circumstances I'm not aware of.

But yeah, if you want to do side objectives or look for samples, I highly recommend doing it before you do the main objective. And use map pings as much as possible.