Well Pike still gets it wrong in the Strange New World’s opening titles. Maybe the English language rule was changed by Pike so that this split infinitive derivation/deviation became standard?
You can can play around with ‘to boldly go/to go boldly’ by exchanging them with other words...
‘To go excitedly to the park’, or ‘to go to the park excitedly’… who cares? Same meaning… the last thing that we need are grammar police! Pike seems to enjoy policing many things, but obviously not grammar!
Grammar as taught doesn't have a lot to do with much of anything, really - certainly not with how a language is "supposed to be" spoken, because there's no correct answer to that.
But some folks like rules for everything.
Split infinitives are fine.