TF2 is a solid choice especially since it's free. The gameplay is straightforward but has depth once you get into it. One cool thing about TF2 is the item and trading system which adds another layer if you're into that. I learned about it from https://robots.net/gaming/gaming-technical-guides/tf2-skin-trading/ when I started playing. You can customize your loadout and trade items with other players which makes it feel more personalized. Overwatch is good too but TF2 has that classic feel and doesn't take itself too seriously. Worth trying since it won't cost you anything