When your body is working well you don’t notice it. It just ticks over like a smoothly functioning machine. It’s only when you are ill or injured that you notice your body. This means that perfect health feels like nothing at all. It’s just an absence of pain.
All things being equal, which I admit they are often not, perfect mental health should also feel like nothing and you are unaware of yourself. If I am going for a job interview then I feel nervous and I am suddenly aware of myself. It is the mental equivalent of having a headache. If things are going well I go about my business almost totally unaware of myself. Being me feels like nothing, just an absence of self-awareness.
Occasionally you can’t help becoming aware of yourself and then it’s better if you have come to accept yourself. If not you might do something like this. Anyway, I think that rather than trying to feel great, maybe an absence of feeling is the best we can hope for.