Do those players also have chameleon suits?
And/or the chameleon skill like Andreya?
A friend of mine said sneak/snipe was useless but I haven't had that problem. He had neither, though, and I have a rare cameleon suit.
I would wonder if the game is taking cues from Fallout 76, where there are three levels of chameleon (mutation, chameleon armor, chinese stealth suit) and two separate stealth perks, plus a legendary and armor color.
The stealth suit is the only one that lets you duck-walk in stealth but you also need a perk to match the Fallout 3 suit.
I was lucky enough to get a chameleon spacesuit around level 12 that I combined with a modded, silenced, rare AA-99 I went bankrupt to buy early (L5) to snipe my way around, even aboard pirate ships I'm "commandeering". (Three so far by L27).
The game has 80+ perks plus skills, gear, and powers.
I'm thinking you need to stack them in combination to get best effect.
For one thing, I have yet to see any muffling mods or skills so getting FALLOUT 3 god-mode stealth might be a high level effort. In the meantime, strategy might be the best substitute for the mod-free player.