Now that apple has their own silicon, all the older intel based MacBooks are pretty cheap. I just replaced my wife’s 2013 MacBook Airs battery, upgraded the drive, and installed Linux. It’s been a solid little laptop. Not the fastest but there’s probably a few pro models within your price range. Just make sure to get at least a 16gb model since the ram is soldered. Might have issues with the webcam, but the wifi drivers are pretty good.
Check out GrapheneOS. They sandbox google play services so you have a lot more control over what is sent to google. Might be a good middle ground.