The last few years, I've had high BP readings in doctors' offices compared to much lower readings at pharmacies. The pharmacy BP machines were shut down early on in the pandemic; so I bought my own for a quite reasonable price. The one I have Bluetooths to an app on my tablet; so I now have a record going back some years which I share with my doctors.
If you have high BP readings while well rested at home with an empty bladder, you need to get that fixed before you get a stroke.