Both my MX keys and MX mouse whatever they're called were perfect when they arrived but over the last few months have become laggy and feel bad.

Across my laptop and PC, both high spec, the Master Mouse thing whatever it's called feels laggy, at first I thought it was debris on the desk but I've been keeping an eye on it for a while and it's not that... it feels as if it's worse when CPU use is higher...as if you're doing in software what is normally in hardware. It doesn't appear to be bluetooth, and shouldn't be as it's separated by <10cm... it's quite disappointing that performance is so poor for such an expensive keyboard and mouse. For the keyboard it's... just...feels slow, no duplicate or missed keys, but it doesn't feel fast, I'm currently on an 8 core i9, it's idling at 7%, but there's a percievable delay between hitting a key and it appearing in this box