Maximum bet is 1 BTC
Blackjack pays 3:2
Insurance pays 2:1
Number of decks is 5
Number of allowed splits is 3
Dealer does not hit on soft 17
Can double after split
Can not hit split aces
Can resplit aces
Can double on first two
Dealer does not peek
Is it normal with these rules that you lose both bets if you
- double down against a 10-j-q-k and the dealer has a hidden ace (blackjack)
- split aces and get 21 on one or both, but the dealer has a hidden blackjack?
perfectly normal
usually dealer's blackjack beats any of the player's hands except for blackjack which is a push usually
this casino's rules are pretty common, no gimmicks ,don't know why are you so surprised
I understand that players hands lose against blackjack. However, where I have played, if you double down and the dealer shows blackjack (not an ace up, but a 10-face) and it's a blackjack, you lose the initial bet and get the double down bet back (since there is no peek in this game)
I will refer you to the Blackjack rules:
https://wizardofodds.com/games/blackjack/basics/#toc-Rules
https://www.blackjackincolor.com/ - one of the best resources, by the way
https://en.wikipedia.org/wiki/Blackjack
hope reading this will answer your questions once and for all