My pref would be a DT (for false alarms, not non alarming reasons) and to contact to the door. If installed correctly they are unobtrusive and if the door is grey etc, then they can be colour matched.
As above a DT won't cure your issue as both technologies have to simultaneously activate to trigger the panel, the PIR element will still struggle in hot environments.
In real terms they are only likely to enter via the doors (regardless of protection) and will go elsewhere.