You could try Toptal. It sucks big time, but it puts a six-figure floor on my (yearly) income, and gives me exposure to a variety of decently paying clients.
It sucks far less than Upwork. The staff and clients are professional for the most part, the clients often value quality work (they actually pay quite substantial rates, it's just that Toptal takes such a big cut). It still sucks, though, to leave so much money on the table, indefinitely, for what amounts to a simple referral - while not being allowed to use Toptal to grow your own network.