Stealth mechanics feedback

In the current state of the game, stealth seems to be an afterthought rather than feasible way to approach the game. There are currently too many factors that prevent the player from being able to approach the missions quietly and should stealth ever be a viable way to play through the game then the following needs to be addressed:

Enemy detection range via line of sight cannot be infinite as it is right now, this outright prevents the stealthing of bigger maps with wide open areas such as oil rig or airport, it makes them excessively difficult to navigate undetected. There absolutely needs to be a cutoff point from how far the player can be seen.

Unalerted enemies should go down in 1 headshot from every lethal weapon as otherwise the number of effective guns for stealth-play becomes absurdly limited as only slug shotgun headshots are consistently able to achieve that throughout the campaign because of the enemy health scaling.

Stealthily killed enemies should not alert other hostiles nearby, this just prevents stealth in general since rouge point has no way to draw attention or hide dead bodies, adding such features would also possibly detract from the gameplay and slow down the pace at which players progress through the levels.

Sprinting is way too loud and alerts enemies instantly, debatable if it should stay that way but with game that has timers on missions & objectives I would suggest tuning it down severely so that it may be used without alerting enemies 3 rooms over at a different floor. Regular walking should not make any sound so that it may be used as the default traversal option it is.

Crouch walking, besides making no noise should somewhat decrease the enemy detection range. If player is moving at such slow pace there needs to be a benefit in doing so.

Suppressors should be the first attachment a player has access to then in turn allow for stealthy takedowns besides making the actual weapons quiet as intended, which seems rather random at the moment. I'd wager that they don't work at all if gameplay is of any indication.

Projectiles hitting terrain should not produce noise that is heard by enemies unless it is within a very close proximity to them, this once again makes stealth harder than it really should be.

Bullets should not go through unalerted targets, as great as getting multi stealth kills sounds, this just doesn't happen and more often than not results in random enemies being alerted to the player.

Interacting with objectives should not alert enemies however it should still draw attention of enemies that are already aware of the player presence.