Casino usually have the x1 wagering requirements with or without bonuses aside from wagering requirements for the bonus to claim it. Their x5 wagering requirements is probably their faucet feature and other bonuses that doesn’t have wagering requirements to avoid potential abuse.
The only odd here is why they only have high wagering requirements on first deposit.
It’s very hard to find casino with license that doesn’t have wagering requirements because it’s one of their way to counter money laundering inside the casino.