I've had issues like this before, my best guess is that since your laptop seemingly isn't designed for gaming (just based on the specs you listed), the cooling solution wasn't prepared for the laptop to be under the kind of load you're putting it under (playing Valorant can be a heavy load for older non-gaming machines). As dust accumulates, that temperature that something like the CPU reaches can climb over time, until eventually it thermal throttles. That what it sounds like the problem may be. To be sure, download a program called "OpenHardwareMonitor" from here: https://openhardwaremonitor.org/
It will list the temperatures of the various components of your PC in Celsius, do not worry though if you see a temp like 50 degrees on something like the CPU or GPU, that's normal for components like that and does not indicate a problem. If you see temps like 80+, your pc could be thermal throttling. It's also important to note that temperatures can vary wildly depending on what else is running on the laptop. I think the best test would be to play Valorant for 30+ minutes and then open the program with the game running in the background if possible (if not, close it and open the program asap after). It will ask for permission to make changes to your computer, this is so that is can monitor the components of your pc. Once you click "yes" or "allow", it will open and display the temperatures. You mostly want to monitor CPU, but GPU could be the culprit as well.
Hope this steers you in the right direction!