Mint is a very narrow margin of efficiency unless you convert everything down to the lowest denomination chips(plastic?) If you do the whole series it is quite profitable but the time invested is very high. Sticking to other products and selling all chips is sufficient in most cases.
The large number of extraction recipes serve as another path to just outright buying the hellirum needed to build the final craft. 12.5k hellirum costs 250 million bought outright. Buying capsules is even less efficient at 775 mil. Add in fuel/ammo for advanced craft, and assorted other uses and you need alot of it. Being able to process outdated/surplus ammo into a form you actually need is a decent feature. Not always needed but really crucial when it is.
You mention a very low resolution being a problem twice. You are aware you can scale up the interface in the options menu? Run the game at a high res, scale up the interface, use one of the filters to mitigate the ugly visuals, and you shouldn't have any issue viewing text. I play in 1600x900 at 1.5 scale and have never had a viewing issue.
There is alot of math to calculate the optimum weapon for a given soldier, but you dont need the optimum at all times. Being able to hit and do some dmg to your opponents is generally sufficient. Trying to strive for that max efficiency per soldier is not worth the micro. Find something that works against most of your current opponents, pack a few alternatives in the craft, and call it done.
AP lasers are indeed quite good at present, but i expect them to get a little worse as the end game expands with more powerful shielded foes. Of the master crafts only the kustom blunderbuss really stays relevant, and then only due to chem ammo's armor shred. 48 potential shred per autofire on top of shred from dmg dealt adds up. And 3 auto shots per turn and still maneuver.
The end game is tedious, but neither is the content for it finished. Effectively most of the third act of the mod is absent but for some signposts and the end goal. So yeah missing content on the way to the end is tedious/dull. Nothing to do but wait.
Some items are indeed quite niche or not that impressive at first glance.
The Destructor is actually really sturdy once you account for its excellent resistances. In practice its the 3rd or 4th most durable armor, 1st or 2nd without green codex. And if your voodoo is up to snuff it has minor regen. As to its inbuilt weapon its pretty much a rocket launcher. Not appropriate all the time, but hey flying rocket launcher without ammo carrying issues. Put a wand, death blossom, or kustom handcannon in the free hand, and you have a assault/breacher/and heavy weapon gal in one unit.
The assassin was once much better overall, but the mod has swung quite heavily away from the smoke/campy style which was the niche for the assassin. And with lok'nar auxiliaries outperforming it in the scout role(NV/thermal being the outfits other high point), the outfit finds itself without a home.
Red codex has a distinctly aggressive bent. Vampy(lifesteal)+blood axe(morale gain)+vodka(staunch wounds) is nigh unstoppable if your not taken out in one go. Add a crystal skull(TU gain for dmg dealt) and you can murder spree many encounters single handed. The Hellblade is one of the most powerful melee and ranged weapons possible in one package.
That said Red is arguably weaker then Grey(Ghost, Witch, and Destructor armor, with higher utility menace craft) and Green(Uber capture tool that is fairy armor and super tank bio armor) but better then gold.
Base Defense is a staple of Xcom in general. Not likely to leave the mod ever considering the work put into making it more interesting. You dont really need a crack team at every base to hold them. Proper base design allows you to funnel most foes into a very small area which you then saturate with flamethrowers and explosives. The only goal in a base defense is to survive, dont spare the firepower. Collateral damage to base facilities is easy to manage. Dioxine even helpfully installed blinky red lights onto the tiles that count for facility damage.