Just a bit of advice for those trying to use a dfplayer on the T8SG V2 plus. First, there was no problem with using the 3.3v power provided on the mainboard in spite of the posts I see where people installed separate regulators. No issues, nothing is hot and all works fine. Second, I could not get things to work until I realized you needed to uncomment "voice-uart5=1" in the hardware.ini file. I had tried everything else and that was the issue.
Someone should add this info to the tutorial.