Effects are applied to layers in AE. In 5.0, text effects are best applied to a solid layer. Layer>new>solid. I believe the text should be applied in “transparent”, not “over original” mode — in the text effect settings.
Keyframe the opacity of the solid, and the text will follow suit.
Adjustment layers are meant to affect all layers below them. Using them to affect one layer can cause trouble later on.
AE is not meant to be used by jumping in. It has its own workflow, which can be different from that of editing apps. A little time spent with the manual can work wonders.
Steve