I can't tell you much more than I have, DreamFIRE. I encourage you to buy a pair from a place that offers 100% refund and try them out. Mine were expensive but have made my life wonderful -in coffee shops, at home, with a wide range of sounds (can't think of any it hasn't assisted with). If ambient sound is lower to begin with, I hear nothing. If it's louder (busy coffee shop), it reduces it. Off, on, and with music added all have different effects for me.
My favourite so far are the Bose QuietComfort35 (over the ear, pre Google Assistant era). I also have the Bose QuietControl 30 (in ear), which also worked wonderfully for me, but I find in-ear less comfy.
I encourage you to try some out, assess and see for yourself.