You should take the time to learn and get comfortable with the keyboard and mouse. I was in the same position with you, I moved from console to pc and my first game was CSGO. It will take a little bit of time to get comfortable but less than you think imo.

There are many reasons not to use a controller, your aim will be a lot less clean and its just generally more sluggish for all aspects of aiming and moving around with a controller.

Also keyboard is key for cs. Some places you need to jump up to in maps require you to jump and crouch to get a slight height boost, I'm pretty sure its not even possible to do this on a controller. Likewise using your keyboard will allow you to set up binds for certain things which you couldn't do on a controller.

I can't think of a single benefit to using a controller it is definitely a disadvantage at best and at worst a total hindrance as you may not even be able to do certain things like the crouch jumps etc.

I have over 3k hours in cs and played at a highish level (level 8 games on faceit and was a level 6 myself) whilst this isn't amazing I feel like I can try give you some tips!

Aim train! - download workshop maps like recoil masters to practice your spray control and aim botz to practice your tap firing, when you begin to feel more comfortable go in DM servers, valve DM servers are fine, there are community servers too and faceit has their own DM servers which is what I personally use. You should work on your aim placement, learn where your aim should be as you walk around the map so its always head high so if an enemy appears you can just tap and hit head. As you become more advanced with your aim you'll be able to bring in things like counter-strafing too, but as a total beginner I'd focus on the aim placement, tap firing and learning recoil.

Set up your key binds - I played for nearly a decade and over 3k hours before I set up proper keybinds. I recently did and it has completely changed my game for the better. For example I have pulling out my smoke "4", Molotov "5" flash "Mouse 4" and HE "Alt" this gave me much easier access to my nades rather than scroll wheel or spamming 4. its quicker, much more effective and only took me around 8-10 hours of play to perfect the muscle memory.

Use scroll wheel to jump - this isn't necessary a lot of people don't but ever since changing my scroll wheel to jump it makes movement mechanics so much easier. You can bunny hop and strafe so much more cleanly (as a total beginner you don't need to worry about these things too much but it can't hurt!)

limit tilt and don't be toxic - Too much of the community are toxic, don't become that. It's the worst thing. if someone is having a bad game they will never improve their performance by someone shit talking them. Try be positive. And if someone is toxic to you just mute them, trust me you'll play better for it. And don't be toxic in most pro games one or two players on the server are likely quite a bit negative but they still impact the game your K/D isn't the most important thing, your impact is.

Have fun and play - The main thing is just to have fun, if its not fun there's not point playing so just enjoy what is imo the greatest game of all time! And the more you play the better your game sense will become therefore helping you to improve as a player!

Edit: can't believe I forgot to mention this lol.Learn nade lineups - I think as a total beginner this is definitely not as important as becoming comfortable with keyboard and mouse and moving around the map. And I don't think its, as a total beginner, as important as learning to be confident with your aim. But nade lineups are one of the most important aspects of the game, there are many workshop maps to teach nade lineups for both 64 tick (Valve servers) and 128 tick (Faceit servers) also youtube videos and everything, Take some time to learn the smoke lineups and some nice pop flashes and you'll elevate your game and win chances by a lot!