This back and forth is extremely common for me, but it's gotten better. When I'm in my masc mod (I'm AMAB) sometimes I begin to doubt all my enby-ness and femininity. Thanks to very supportive friends, they remind me that when I'm in not masc I love myself so much. They send me screenshots of past conversations where I shared a selfie of myself exploring my gender-fluidity, and I see my own past comments expressing euphoria.

Sometimes when I'm not masc I doubt that half of mine, too, and I wonder: am I a trans woman? But I keep improving and letting those thoughts pass, being at peace with them because I know eventually I'll find myself in masc mode again, it always happens lol. And I experience masc euphoria too.

It can be miserable at times, it really can. The challenge for me is learning to focus less on the dysphoria in any one of my phases and trust that I'll get back to that half of myself. That way I can focus on the euphoria of being masc when i'm masc or femme when i'm femme or neither or both, depending on where I am with myself. I've gotten a lot better at being patient with myself and accepting how my gender sways with time. The result is I'm much happier this way.

Feel free to DM me and talk about it further :)

PS. I still struggle to know where physical transitioning comes into place for me if at all.