Your story sounds so much like mine. I have since wondered if I should have given in (or tried harder to find an expert working through Covid) as the first weeks I put myself through hell, compromising those early days and I don’t know if it was worth it. I am still feeding now @ 7 months, we did get there though.
You’ve had such fab input but just a couple of things I’d add from my experience would be don’t judge your supply on what you can pump. You can have an excellent supply and not be able to pump. I’ve never even leaked yet my supply is perfectly fine. The only way to judge is weight gain.
Also, after her tongue tie, as others said, my girl was really fussy at the boob, it wasn’t a supply issue, just relearning. She also took in a lot of air by fussing making her uncomfortable after a feed. Took me a while to cotton on to that.
I had a tendency to make everything about not enough milk but after supplementing her with formula, it wasn’t that, she was just unsettled like so many babies can be and possibly has CMPA.
If you do supplement with formula for one or two feeds, it doesn’t mean your journey over, plenty of people combi feed. I did it for the first month or so, a formula feed every other day probably, then stopped with the CMPA diagnosis and it was fine. Just keep monitoring her weight and it will tell you what you need to do.
You may not be the same as I was, so ignore if so but I was obsessed. The fundamental thing, to feed my baby, I was failing at and I absolutely would not be beaten by it no matter how painful, upsetting, difficult it was for me because I wasn’t failing my daughter. Ridiculous to think now, (though Covid meant no weighing after the first few weeks which didn’t help) but looking back I wish I could have been less frantic and looked at things more clearly to realise there were other explanations for the problems and loads of signs she was perfectly nourished I was being blind to.