The learning curve isn't that step anymore, especially for Singleplayer - even for more experienced Arma Players the main frustration there is the "trial and error" factor in the missions. Online it's a bit different - if you don't play full on MILSIM and focus on infantry combat you will be good there as well. It's all manageable these days. And still great fun.

ArmA 3 genuinely has great tutorialization. They teach you the controls, why you would want to lean certain ways, and so forth. And the campaign (as long as you completely skip the free roam modes...) similarly does a great job of teaching you why you would want certain optics or even how to navigate.

That said... the mission design is still horrible. Been a couple years since I tried it but I remember always getting hung up on a town defense mission that is supposed to be highlighting drone combat and the like. But the mission briefing and all the comms are "enemies incoming!" with no indication of from what direction. Which is especially egregious in a milsim where you would, bare minimum, get "from the South" if not "last spotted at compass heading 2 2 4" or whatever.

Which has been a problem since OFP. The missions are designed with trial and error in mind and I am just too old for that shit.

Also as a fun story. I played the ever loving hell out of Operation Flashpoint that was set in the 1980s. Fast forward to ArmA 1 coming out and me being super excited and.. it took me far longer than it should have to understand how a red dot sight is supposed to work. Kept trying to guesstimate point of aim (since you kind of have to do that with iron sights and a post) and took the girl I was dating at the time to ask why I am not just putting the red dot on the thing I want to die.

Which is why, to this day, in games like SPTarkov and H3VR I still prefer to have the front sight on even if I am looking through an optic.

I have player the original arma (operation flashpoint) and Arma3.

And while there is a ton of depth, you can ignore part of it if you want to play more casual.

While you can know all the details of a weapon at a ridiculous level, you do not need to know them to finish the campaign.

For multiplayer I can't help as I've never played it. But I suppose it would depend on the server and which people you play with.

You don't have to miss it. It is still there and enjoyed by thousands of people everyday still.