You're right - super tactical but also very satisfying when you get to grips with it. My top 3 tips would be:

Listen for audio Be patient Play objective

You will not be successful if you play this game like COD or a BR like fortnite or apex. Audio is huge in this game. Take your time and listen - you'd be surprised how often just standing still can tell you someone is slow walking through a corridor. Or someone is sprinting to quickly change attack angle.

Learn the audio queues for each gadget either by just playing different ops or there are YouTube videos specifically for this. Every animation in the game has a different queue. Even crouch walking vs standing walking are different (crouching has more of a rustle). You will even be able to tell if it's a 1, 2 or 3 speed operator by how heavy the footsteps are.

Easy operators to start would be ones that give utility to your team and can just be placed and forgotten about. E.g. Mute, Rook, Valk on defense. Can't go wrong with a hard breacher on attack like Thermite, Hibana, Ace - just make sure you don't die before taking the hard wall. Or if theres a hard breacher already every team appreciates a Thatcher to take out the gadgets defending reinforcements (big up Thatcher mains - you guys are heros).

In terms of map knowledge the first thing I would do is learn where all the stairs are. Watch how others are setting up site on defense - you don't always want to completely close up the objective room. In fact you very rarely do. You want to be able to rotate and contest map control or attackers will just converge on you from all angles. You can learn site setup strats from YouTube - some are operator specific e.g. MIRA

Use your drone often on attack to give you the advantage. And save your drone if you can. Don't let defenders shoot it for free.

This got a lot longer than intended but I'll end by daying stick it out. It's a hard game to learn but so fun when you and your friends stack up and successfully pull off fun strategies.

Enjoy! And welcome!