Maybe not a warrant, and IANAL, but government agencies aren't necessarily at liberty to share information amongst themselves. For instance, IRS needs a court order to share returns with law enforcement (IRC Section 6103(i)(1)).
But yeah...this seems like maybe not a super great solution...
I have an old Nexus 6P, spiritually the Pixel 0.
Replaced the battery at some point, and it's now entered service as the toddler's entertainment on airplanes.
It's old and slow, but the screen still looks really good.