Need advice for aiming arrow

I want for my player something like this > 404 Not Found (or https://hackerbot.net/images/games/brawlstars/brawl-stars-aimbot.png), the green path (in my case an arrow) showing where aiming. It’s direction respectively can change, also length in my case (how far I want things to throw), and also angle up down. Im using top-down template c++. Would be nice if someone would kickstart (give idea to) me, how do such thing. Performance is critical, as i is for mobile.