I think ‘having a hard time trust anyone’ is a good approach to have to be honest.
For me personally as someone who has only come onto grey in the past few months, I’d recommend reading widely on the forum reviews for vendors on this website, and then join the discord for some of the ones that seem widely used to chat to some people who use that product + see if they’ve done their own group tests in the past.
It’s easy for everyone to say ‘just test everything you use!1!’ when it actually isn’t that easy or cost effective to organise a test yourself, nor is it easy to find a group test that’s occurring at the same time and using the same batch you MIGHT get.
Unless you’re willing to wait a few months, at some point you have to just take the plunge on the vendor you’ve noted has had genuine good reviews on this website, has been around for a while, has potentially had some group tests in the past with previous batches and seem to have happy + returning customers on their discord/telegram.