I grew up in Illinois. Hunted deer with slugs until I was well into my 20s. As did everyone else.
A smooth bore with a bead is MAYBE a 50 yard gun due to sight accuracy. Brenneke are excellent. You’ll need to figure out if the vent rib has built-in rise or not, as that changes impact point. Improved choke or bore cylinder only. Rifled slugs only- the “rifling” is so it can swage through the choke, not to spin the slug.
Smooth bore in a slug barrel extends the range farther, to whatever range you can accurately shoot. Usually 100 yards. Rifled slugs only.
Rifled barrel with a sabot slug gets you to 150. I used Cor-lokt and copper solid slugs. Killed a bunch of whitetail to 120 yards hunting the woods.
Bolt action platform of the above can get you 200 yards on deer. Uncle enjoyed his until shoulder surgery.
I would say that you’re better off with a 20 gauge, and limiting shots to 150 yards in a scoped gun with a rifled barrel and sabots.
Slug guns are great for moose because thick brush and close shots mean you need to punch through brush to get to the moose and then put a big hole in them, but there isn’t a chance for a lot of bullet drop. Heavy projectiles have a lot of momentum work for that.
For elk? Usually they aren’t in the thick stuff like that, so I’m not sure it’s the best option.