Apologies for the long reply, but I really sympathise with you and hope this helps!
Both of my babies were tongue-tied. My first baby’s TT was diagnosed quite late and unfortunately we never managed to recover exclusive breastfeeding (but we did manage combi feeding for 11 months). However we did salvage things with my second baby and I’ve been exclusively breastfeeding for almost eight months now. Her TT was cut on day 2 (like you - super lucky!) and she was able to latch, but it wasn’t perfect. It took a lot of effort each time she latched on to get it right - the best advice I was given was to never accept a bad latch. If it’s not perfect, take baby off and keep trying until the latch is right. Only then will baby have the best chance of withdrawing the milk.
After about three weeks, breastfeeding seemed to get worse - she was frustrated when feeding and I was getting sore again. I took her to the feeding specialist at the hospital and it turned out that her TT had reattached when it healed, so it needed to be re-cut. Once that was done, breastfeeding really improved. I would highly recommend getting baby assessed to see if the TT needs to be cut a second time.
We also saw a cranial osteopath as my baby had a high palate, recessed chin, and a lot of stiffness in her jaw (we think due to a very fast delivery). We had four or five sessions and that seemed to really help the stiffness in her jaw and her ability to latch. Some cranial osteopaths are also infant feeding specialists and come with so much knowledge about breastfeeding!
I also found that baby fed better in certain positions - the rugby hold was especially good for helping her latch whereas she really struggled with side-lying. I would suggest trying all sorts of positions and finding what works best for you and baby.
Also, you could try hand expressing a bit of milk before feeding baby so he doesn’t have to suck for so long before the milk lets down - saves some frustration!
At the start with both of my babies I did everything I could to build my supply. That meant letting baby be on the breast as often and for as long as they want in those early weeks. I also pumped in between breastfeeding sessions to keep my supply up whilst the baby wasn’t effectively withdrawing all the milk. It’s all a bit of a faff, but if you can push through those first couple of months it will be worth it. It all settled down for me around 12 weeks I think.
Having said all that, do whatever it takes to keep baby happy and to keep you sane! A fed baby is a happy baby so if that means bottles, then go for it. The newborn stage is hard enough as it is, so make sure you look after yourself as well!