The link to the PIR lens does not seem to work anymore (404 not found error).
Did you try e.g. https://www.aliexpress.com/item/10PCS-Infrared-Sensor-8308-4-mini-White-Fresnel-Lens-body-pyroelectric-PIR/32780943866.html ? This lens seems even smaller. Or are there disadvantages to being too small?