Does anybody trust these privacy labels? What keeps companies from submitting some labels and be done with it? While still track everything for whatever purpose they like? Nobody can check what they are doing on their servers.
Also the labels are not so much about what data is sent but about what the companies do with the data. Example: Do they just use your position once to show you relevant search results, or do they create a location history of you? Do they sell that history? Do they combine it with other data about you? There is no way to know.
Of course you can, just configure your phone to use a MITM proxy (e.g. burp). This won’t work for apps that use certificate pinning but most apps don’t.
Of course, you still don’t know what data they really store and/or sell.