New to collecting. Are any graders trustworthy. I keep seeing flimsy stuff and conspiracies

For example, saw a guy post a video about how his pikachu promo card got a 5-6 then re-sent it under a more “expensive” grading package and got a 10 from PSA doing both grading. I want to use gamestops service because they sent to PSA but I’m afraid because I didn’t spend enough money. PSA will never give any of my cards a 10 even if they deserve it and will force me to either live with it or resend it under a more expensive package.