New Mac Mini. Noticeable lag between clicking menu items and the response. Was never the case before. Any help?

I’m using an M4 Pro mini with 48GB RAM running macOS 26.6.2 and using Ps 27.10.0. I received it last month and set it up fresh, not using migration assistant. 
I haven’t seen any lag between clicking menu items such as Filter > Blur > Lens Blur or Filter > Blur > Gaussian Blur, or Image > Apply Image, or Filter > Liquify. 

It would be helpful if you could provide more information about system specs and which macOS on the mini and which exact Ps version you are using. New mac mini and latest Ps can mean a variety of things.

Ran into this on my own machine when I set up a new Mac last year. First thing I'd check is whether Photoshop is running natively or under Rosetta — right-click the Photoshop app in Applications, hit Get Info, and make sure 'Open using Rosetta' is NOT checked. That one toggle alone caused exactly this kind of menu lag for me.

If it's already native, go to Preferences > Performance and uncheck 'Use Graphics Processor', then restart Photoshop. On some of the newer Macs the GPU driver and Photoshop don't get along and the menus take a beat to respond. If that fixes it, you can re-enable it later and switch the drawing mode to Basic.

And if neither helps, hold Alt+Shift right when you launch Photoshop and reset the preferences. Fresh machine, fresh install — sometimes a migrated preference file is just off. Curious which Mac Mini chip you've got too.