Is RebelBetting worth it in Germany?

Now this is a Question that maybe only Germans can answear, but maybe others can help too.
Of all the Bookie i have seen here, only Bet365 is the one i recognize being available in Germany and which also seems to be the most profitable. But most of the bookies i read here about are not available in Germany. Other known bookies i can use in Germany are: Betano, Bet-at-home, Tipico, betway, Bwin, Xtip, 888sports, Interwetten and more. Now since i havent seen these Bookies being mentioned here alot i wanted to ask if anyone has experience with these. I really dont like thinking about using Bookies from other countries that arent available in Germany without VPN, because i am scared that somehow it will go wrong and i wont be able to cashout my money. Also the reason i ask if its worth it in Germany, is because we have to pay 5% tax on every win. Isnt this a long disadvantage in the long term?
I would be very happy if someone who is familar with the German Market can tell me what the most profitable way to use RebelBetting in Germany is?

Regarding the 5% tax… When bettors “borrow” somebody’s account they pay around 20% of the profit as “rent”. And it is still profitable!
Of course 0% is best.