Interactive Brokers is also my next choice. Although, beware that you have to install Java runtime from Oracle in order to be able to log in to they servers. Java runtime environment has seen many beaches of security in the past, particularly the Internet was still in adolescence. Oracle claims to have solved those but this needs to be verified.
I’m waiting for Schwab mainly because, as it turns out, there is magic there. Namely, our assets are protected from online fraud. I’m sure there are limits to that protection. And that protection has applied to their normal online accounts. Will it apply to API accounts? We will have to reread the fine print when it’s final.