Bybit is superior to Bitmex in a lot of ways (order submission, customer support, etc.) though if your main purpose is to avoid the region ban, not going to make any difference.
I believe Kraken offers margin trading for US residents, no? Bitmax is worth a shot as well, though hasn't been around as long so doesn't have quite the same track record.
2) Use a VPN, use Bitmex or ByBit
Paid shill alert. 'cryptoadvocate' consciously embedded a bybit referral link while bashing other exchanges and intentionally neglecting Deribit that has much better track record and thicker order book. That pkoz6 in the link is probably his/her bybit id.
Bybit should be called shill-bit instead.