Yeah my bo problem started when I was in a period of big stress too.
I started noticing when my anus sometimes felt like it was relaxing, as if I was about to have a bowel movement. Smells and leaking could escape because of the looseness, but in normal people it's sealed shut.
I think both sphincter rings are supposed to be tight and the 3/4 is pretty normal but you need to try kegels to see if that's normal for you. Be aware of any redness or itching cause that could indicate leaking. Once you diligently do kegels, you'll see just how tight it can really be, how much better if feels (lol), and you might just say to yourself "okay so this is what it could normally feel like".
You can compare that to how people don't stick out their stomach while walking around; everyone naturally, without noticing, has their core engaged and they don't on purpose TRY to protrude their stomach . Don't know if that makes sense.
If you try kegels make sure you try different durations your are holding the squeezes, and also different intensity and deepness of the squeezes.