GPS tracker for an interstate move

My parents are doing an interstate move in a few weeks, and I want to get them a gps tracker that they can put in a box to help them track their stuff. The main goal is to provide them their own data if they get into the situation where the carrier and the trucking company are blaming each other for not knowing where their stuff is.

Tracki, Ameriloc, and LandSeaAir seem to be the big names, but there's very little signal and not much independent information. Also a ton of products on amazon in the <$30 range that seem indistinguishable.

Even several hundred dollars in cost is not a deal breaker here, considering the issue of their stuff, but I didn't really find a clearly better expensive option.

Whatever I get, I also plan to get two airtags as backup. Maybe that's enough by itself, but I like the idea of having an active option, even though I know they could all fail for different reasons.

Has anyone used one, and if so, what was your experience? What would you recommend using or avoiding?