A lot of paid cert providers were not so great before LE put the spotlight on the issue; it was more of a scheme to extract money from operators who couldn’t afford to not offer TLS / SSL. https://bugzilla.mozilla.org/show_bug.cgi?id=647959 was a famous post that made fun of / criticized the system before LE. This hurt security, and if not free, LE wouldn’t have worked.
I was also with a provider that didn’t offer API access for the longest time. When they then increased prices, I switched, now paying a third of their asking price per year at a very good provider.
I guess migrating is difficult if the provider doesn’t offer a mechanism to either dump the DNS to a file or perform a zone transfer (the later being part of the standard).
Can only recommend INWX for domains, though my personal requirements aren’t the highest.