With an FPS game it’s definitely worth it even you don’t achieve 144fps. However you setup should be fine achieving 144fps in Valorant. There are modern games that will run poorly on you cpu but with this it doesn’t matter what monitor you have. Just make sure to research the monitor, just because a monitor says 144Hz does not mean it’s good, I’ve seen some reviews very poorly.
Of course you should get a 1080p 144hz. If you are jumping from 60hz then that's a perfect next upgrade. Even if you don't maintain 144fps and it dips in the 80-144hz range it will still feel better than a standard 60hz. I would simply use RivaTuner that comes with MSI afterburner. Set a cap for 142fps in RivaTuner, leave Vsync always off, enable Gsync features in Nvidia Control Panel, enable freesync in the monitor menus and then every game lower the in games settings like AA, shadows, post process till you hang in the FPS range you want. Make sure to use some sort of on screen FPS display. Old games will run great and give you a taste of constant 142 frames, new games will get you thinking about AM5,AM4,12400F, etc. Never hurts to buy a little more monitor then what your system is up for running at Ultra. Gives you room to grow a little when you drop in a future 3060 or better. Then you can crank all the settings and still run close to 144fps.
The fact that you are shopping for 1080p is what makes it a realistic and good upgrade. Your GPU/CPU can handle 1080p pretty good depending on the game. Just make sure to set it up like I described to get the most out of it. You could even consider 1440p 144hz. Old games will still run well on it newer games will give you less FPS then 1080p of course. It will get you itching for a GPU upgrade sooner. My young kids PC has a GTX1070 Strix/Ryzen 5 3600/16gb 3200mhz/1tb SX8200 on a 144hz 1080p 24" screen. Works great. Also run basically the same 3600/1070 setup on my wife's 240hz 1080p screen and games like Rocket League run locked at 238fps as I always cap my frames. She's not even a gamer but the few times she games with us I wanted butter smooth 240hz/240fps gameplay to help with motion sickness that 60hz brings. I cap my frames to maintain framerates within the adaptive sync range of the monitor to avoid any tearing. Also it allows me then to simply drop game settings until I'm averaging around the upper range of the monitors abilities.
Newer games you will need to decide if you want FPS or Quality detail settings. You will have to drop down the detail very low to maintain higher FPS. Older games like Portal 2 you can have 144fps and High Detail. PC games you simply need to tweak your settings to get what FPS you are shooting for. And of course newer games at LOW detail will still only get so much FPS likely not 144. Lots of flexability on PC's to tailor your hardware to the game and the monitor being used.