Piano (and other musical) skill is not at the same level as gaming, or sight-seeing. More than singing, instrument playing require absorbency and perseverance. Like jogging, it strengths self-efficacy, raises self-esteem,,,

Musical journey is a struggle. The level of struggle is between the level of recreational workout and bench-marked workout. There’s some form of penalty if you don’t put in a minimum amount of practice .. you end up achieving nothing and you waste your effort. As such it demands a minimum commitment.

If I make very slow progress with a tough piece, I can feel disappointed and frustrated.

I need to select reasonable songs. what if I make very slow progress (stuck) with one song? How do I motivate myself?

— sink, buffer, slack resources
Piano practice is an excellent energy sink. If 3H/week, then it becomes a good reserve of slack resource, a buffer of extra time. See blogpost on buffers and alternatives.