Most (alL?) local rank trackers just use URL parameters instead of proxies.
Relevant URL parameters
The three relevant ones to localize search results are:
&hl=
for the language
&gl=
for the country
&uule=
for the exact geolocation with longitude and altitude
Example
Instead of using the URL https://www.google.com/search?q=bakery
to look at the search results, they use https://www.google.com/search?q=bakery&hl=en&gl=US&uule=a+cm9sZToxCnByb2R1Y2VyOjEyCnByb3ZlbmFuY2U6Ngp0aW1lc3RhbXA6MTY1ODU2MzQ3Mzg0MjAwMApsYXRsbmd7CmxhdGl0dWRlX2U3OjM3NDIxMDAwMApsb25naXR1ZGVfZTc6LTEyMjA4NDAwMDAKfQpyYWRpdXM6OTMwMDA%3D
Ideally, also throw in &pws=0
to avoid any kind of personalization.
Free Tool
Here is a free tool to translate an address into a geolocation and automatically start a Google search for it: https://valentin.app/