It seems that some Windows computers are generally laggy with no good reason. I could recommend installing Old Calculator.

https://winaero.com/get-calculator-from-windows-8-and-window...

It was a little difficult setting it up so that the calculator key on the keyboard pulls it up but aside from that it works well.

Probably a cache thing. Win11 precaches a lot of stuff if you hover over it or have excess RAM. It's not as smart as SuperFetch and ReadyBoost (with an HDD) was but it's still doing similar things.

Instant for me but I have a beefy CPU Ryzen 9800X3D and some crazy nvme.

And most important: no corporate spyware disguised as anti-virus, in this machine.