It may not be what you are looking for, but the way I go about this is by releasing the the strap until the end is about 5cm from the buckle, and then step out of the harness. The next session, you only need to tighten the strap so the feeding etc. is not needed. I call it “skirt” style.
I use to have a Mystic harness with the clip you’re looking for, and it gave me some scary moments as the clip can unhook by itself - even if put on reversed (inside to outside) like in the picture.