What might have changed since all was well?
Possibly an app or malware was installed.
Perhaps a bad windows or driver update.
Look in your installed program list and see if there is anything installed recently, particularly something you do not recognize.
Uninstall it.
Do you have any apps that might be running at higher priority than your games?
Discord, streaming or...?
Use system restore to reset your pc back to a time when all was ok.
My canned response to laptop performance issues:
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I see many complaints about gaming laptops not performing well.
Usually gaming while plugged in.
One common cause is thermal throttling.
Laptop coolers must, of necessity be small and light.
The coolers are also relatively underpowered.
If you run an app such as HWMonitor or HWinfo, you will get the current, minimum, and maximum cpu temperatures. Set to see each individual core.
For intel processors, if you see a max of 100c. in red, it means you have throttled.
I think the number for ryzen is more like 85c-90c.
The cpu will lower it's multiplier and power draw to protect itself until the situation reverses.
At a lower multiplier, your cpu usage may well be at 100%
What can you do?
First, see that your cooler airways are clear and that the cooler fan is spinning.
Use a windows balanced power profile, not the performance profile.
Set a minimum cpu performance to something like 20%
It is counter-intuitive, but, try changing the windows balanced power profile advanced functions to a max of 90% instead of the default of 100%
You may not notice the reduced cpu performance.