From assumptions, the mod on stealth is probably to the point that unless you are nearly maxed out, being seen is a matter of time and distance. Most of the realistic stealth mods do similar balancing, so thus my guess. My stealth isn’t that high right now so I definitely see the same issues with it failing once I hit a certain distance from a subject looking my way.
I’m kind of at the point of needing a follower. That has never been my Skyrim “style” so I’m in the same boat. I consider this a learning experience for the mod pack. I’m sure all the balancing with multiple enemies and strength of enemies is based around that, so attempting a lone wolf approach doesn’t make too much sense.