Be patient, the technology continues to advance and will eventually become better on your phone. Transcribing is a processor intense process, and even when it involves a computer, with its more appropriate hardware for the purpose, you'll need a pay-for application to get consistent and reliable results (the free ones typically being 'OK' but not as robust).
Also, while the current trend is to scorn Google's hoarding of user data, things like the AI (Artificial Intelligence) research now being applied to voice commands, and something like transcribing development, are a direct benefit from all that data-mined voice recording data.
But even with AI becoming prevalent, there's still an active market for transcribing services that still rely upon people to do transcribing, old school. They sit at a workstation, listen to your audio content with head phones, and type the results using physical keyboards. So some of us are actually impressed that transcribing on a smartphone is even a 'thing' at this point.