You know you can keyframe the Source Text property in the Essential Graphics panel with those keyframes showing 1 letter or 1 word at a time. It's a little tedious but worth exploring. If you want transition that does this, Film Impact makes one in their bundle.
This could be achieved pretty easily by offering a "basic typewriter" MOGRT on Adobe Stock with options to change the font, size, and fill color.
I guess the reason it's not already on Adobe Stock (I did a quick search - only found paid options) is that it's fairly easy for anyone with After Effects to create their own. Or if not a MOGRT, just import the Comp directly into Premiere Pro. It's more to juggle though.