Do-all
I think the OP is on the right track with a pump. A manually operated repeater, theoretically, a GOOD pump should be 100% reliable and less finicky than an autoloader.
In my book that leaves two choices, the Rem 870 family, and the Mossbergs.
-The Rem 870 family has two branches, the 870 Wingmaster, and the 870 Express. The Wingmaster has a longer history and is seen as their flagship pump. Early guns were blued steel and walnut, with fixed shokes, and did not have choke tubes, although that feature was added eventually. (more on that later). The 870 Express cuts some corners in wood and finish and some internals, and is more of a recent pricepoint gun. Many believe the Wingmaster is better constructed/fitted and the better gun of the two and I'm inclined to agree.
The Mossberg family has several models as noted. The Moss 500 is their bread and butter gun and has been around a long time.
Early guns had fixed chokes. and again, tubes came later. Early Moss 500's were 2-3/4" chambered, then 3" when the bigger shell hit the market. The Moss 535 is essentially a Moss 500 that has been adapted to chamber and fire the even bigger 12 gauge 3.5" shell. The Moss 835 is similar, but w/ added features to allow the firing of the big 3.5" shell more comfortably. If you are not a dedicated waterfowl or turkey hunter, you will not need the 3.5" chamber in your shotgun and can nix the 535/835 from your choices. Truth is, you likely don't need the 3" shell either. The Moss 590 is a a dedicated SD/HD/LE shotgun, a beefed Moss 500 up for rugged use. I am not aware that it is available in any barrel length except short 18.5-20" versions intended for SD, and I believe all use an extended 7-8 shot magazine.
Barrels- Sporting versions of the Rem and Moss come with interchangeable barrels and all sporting guns now have choke tubes. Choke tubes are metal cylinders of varying constriction that thread into the muzzle of the gun and effect the size of the shot pattern, or cloud, as it travels to the target. Though criticized earlier, an acceptable length for a GP pump shotgun barrel is 28". The 24" barrels are handier, but are thought to be a bit of a compromise when shooting at flying game due to a shorter sight plane and lighter weight, effecting swing. My old Remington has a matched set of 26" barrels, with fixed chokes, and I see it as ideal, but I do not think Rem offers a 26" barrel and their future as a gunmaker is now unknown.
Given the murky feature of Remington, I'd get a Mossberg 500 w/ 28" barrel and 3 choke tubes (IC, Mod and extra/ turkey full). Standard 2-3/4"* 1 oz* 12 ga lead shot shells with #5 or #6 lead shot will solve about all your sporting shotgun needs for starts. If the world ever gets sane again, a short slug tube can be had for around $100 bucks and buckshot or slugs for deer or SD. should you want one.