As someone who's had a severely-affected tongue-tied baby, you're doing everything right.
You're doing an amazing job feeding that many times a day. You must be exhausted.
It's a vicious circle for your lo, this tongue tie business. Your ds has to work harder to get milk, which tires him out, and causes him to use more calories and makes him hungrier more quickly. Plus, an inefficient suck generally means lower supply, so he gets less milk (than if he didn't have tt) and therefore gets hungry more quickly.
My lo had a 'mild' tongue-tie too, apparently. But its effect was not mild in the least and baby had hardly any tongue flexibility.
The good news is that treating the tongue tie will change everything. The hard thing is getting there.
In my experience, what made a big difference to both of us was my taking a few days of almost exclusively expressing to build my supply (feeding ebm or formula depending on what I had). Baby was more settled with a full belly and I felt more confident in re-establishing bf once my supply started to look more 'normal'. After the snip, we were exclusively bf again within 4-5 days. It was very hard to believe the change in our house in such a short time.
Just to note, my supply was badly affected by the inefficient feeding (I could compare with my older babies), so I don't know if we'd have managed to fully establish bf after the snip unless I'd re-established my supply by breastfeeding. Lactation consultants didn't agree with my decision to try to build supply at first, but I knew my body and I knew I didn't have enough milk compared with my other kids. When they saw the difference in my supply, they admitted that they hadn't believed I would be able to rebuild it and continue bf. They were more concerned about bottle feeding in the interim, but that time bottle feeding saved the bf relationship.
I suspect a few days of expressing might work to make everything a whole lot easier for you and your ds in the coming weeks.
Above all, trust yourself. You got this.
(sorry for the essay)