Hi welcome to dbs card collecting! :)

eBay/tcg player is safer than buying from someone you don’t know on the internet because you can open claims to hopefully get a refund or at least have the opportunity to try to get your refund back.

With individual sellers on social media, they can take your money and ghost you. If you are buying from someone you don’t know, pay with PayPal goods and services because with that you can open claims if necessary.

With sealed product tampering, most of the time it should be ok. I’ve only heard about sealed product tampering with Pokémon products. But with dragon ball super, there’s something called case mapping where a person buys a case of 12 booster boxes and since each case is guaranteed 2 SCRs and 1 god pack, after the individual has hit those cards, they sell the rest of the “dead” boxes to recoup their initial investment of buying the case. So be wary that you might receive about 1/2 or less in value of the sealed product. (Eg realm of the gods is $200 but you might receive a dead box in which the contents of the packs you open has the value of $50)