X-Com 1 and 2 (new versions) are great games, even if they moved away from the large squad slaughter that was Enemy Unknown, terror from the deep and partially Apocalypse. I personally really enjoyed looking at black sections of the map and thinking "that will cost 3 rookies to explore"
Everyone is aware of the "95% to hit meme" around X-Com, and if you've played Phoenix Point, the difference is especially jarring. If you haven't, aiming in that game is purely a probability cone, so standing point blank next to an alien means something. In X-Com it doesn't mean diddly squat.
I finally figured out what the problem with X-Com is, and why it's always uniquely frustrating. With it's pod based mechanics, fake stealth and drip fed enemies. What you are seeing on screen has no relevance and only serves as a distraction. Being right next to an Alien and missing is irrelevant because where the character and alien are on screen do not correlate with the game.
X-Com is, for all intents and purposes a very fun card battle game. If it were a Dos prompt game, with exactly 0 visuals, nothing would be lost.
Try it next time you play, completely ignore the visuals and imagine your character as a card drawing a dice based attack against another card.
Having played both of the nu-Xcoms on release it has always been active seeding, down to the enemy placement. Any move you take changes the seed, enough so that save scum advice often became "use your blue move differently" or "attack in a different order."
But it is seeded, which means yes if you load just before a combat roll and redo the same action it'll stay the same. Which again is easily reshuffled with something as simple as moving in a different order.
If you save scum hard and often enough, as I did when I was worse at the games, you can see that even things that should be "beginning of map rolled" aren't like enemy pod placements, which is why you can go multi-turns without seeing a soul and then see 9 enemies in the same turn.