I just installed my PSE 2021 download, the Tutorials refer to, "Photoshop Elements 2019 ??

It should be, but it isn't!!  Adobe is cutting corners with its Help files which are confusing and often outdated.

However, most of what you see for Elements 2019 will be applicable to Elements 2021.  If you scroll through the tutorial cards on the Welcome Screen, you will see some with a blue what's new sticker.