I would suggest just cleaning up your software a bit maybe try finding a decent program that will help with that like iobit or something similar. I feel like the lags you are talking about are coming from a well needed tune up and clean of your ssds. Your hardware is still good and shouldn't be causing stutters. But also if you wanted to upgrade you would have to do gpu, cpu, and then probably motherboard and ram so I wouldn't suggest upgrading hardware.