if you have WOTC expansion you can set up timers to be longer. Failing that, the True concealment mod sets it so that the timer doesn't start until you break cover or fire the first shot. So you could potentially scout a bit or get closer to objectives before you go loud.
That said, i played Xcom2 standard, with and without the timer mod and with the time extension and its fairly doable not at any point did i feel like i didn't have enough time. You get use to moving quickly, but then again i saved scum so yeah...
when i played Xcom2 i went slightly crazy modding cosmetics. one mod i would recommend the Gotcha Again! mod for QOL stuff. although it conflicts with the perfect info mod apparently.
I don't have the DLC so I can't change the timers without a mod, but so far they haven't been a problem.
The Gotcha Again! mod looks very nice though. I've already had problems with not being sure if I would be able to hit an enemy after moving, so I've subscribed to it.
XCOM2 is one of mine and my wife's favorites. We have over 400-hours in it, having completed several Commander-Ironman runs. There are a heap of mods I would recommend, but going through all 56 of them might be a bit much... But I'd definitely recommend the one to disable timers while your team is concealed; to me, that just makes sense. Another I recall off the top of my head is Aiming Angles, which guarantees critical hits if you're flanking, though it does the same for the enemy, so be careful.
Honestly, I recommend pushing through pretty much no matter what happens. The game is pretty completeable even if you lose a whole bunch of soldiers, as long as you have a solid rotation of them being trained; I'd recommend an A and a B team at the very least. Also WotC is required, as it just balances the game so well and while the Chosen do tend to be tough, some of the weapons and upgrades you get off them will give you a dramatic power boost.
It seems War of the Chosen is €40 right now, but the lowest it's been ist €2.79, so I guess I'll just hope it'll be on sale again sometime soon.
I'm a bit conflicted on doing an iron-man run. I loved doing iron-man for the first XCOM game, but I had a lot of time to game then, so losing all my progress wasn't that big of a deal. Nowadays I'm lucky if I can play like 5 missions a week.