If you are US based my first choice would be BetOnline.ag. They been around for several decades and are certainly trustworthy. Mainly focusing on US sports and the US market. 1.91/-110 lines on most of the big leagues. KYC after a certain amount (read the TC before signing up).
BetCris, very similar to Betonline.ag. Been around for ages and are trustworthy. Focus on US and US sports.
Both of these sites accept highroller bets without running into problems. $15k on a NBA/NFL match should not be a issue. The webdesign is old and outdated and bitcoin withdrawals takes up to 24 hours, but other than that they are top notch and you can be certain to be paid your winnings.
If you are comfortable playing with a VPN I would go for Sportsbet.io. They are trustworthy and offer instant deposit/withdrawals. Odds a bit on the lower side compared to Betonline/BetCris.
Most bookies dont want US action. You already gambling if you choose to break T&C when signing up from a restricted area with a VPN.
If I were you I would accept to wait a little longer for my withdrawals and place my action with a US friendly book.
This is a funny post, and shows where you are paying for the marketing with worse odds. Did you know that LowVig is a sportsbook offered by BetOnline? They offer no promotions, only reduced juice. You only see marketing ads for BetOnline and Sportsbetting, both owned by BetOnline. However, LowVig is also owned by them. Check them out sometime.