Hugs honey, you haven't broken him and sleep deprivation is not a competition
any time we're not getting the rest we need it's rough, even if someone else's nights are objectively 'worse'. So I really do feel for you, it sucks being so tired.
Hmmm, it's a tough one. I feel like there are maybe a couple of options. One do as you are trying, one blankie only and use GW to remove your presence once he is managing with one. Two, cold turkey remove it.....I'm not so sure that's the way to go though, I mean, it is a comfort item that (apart from providing dry ones) he can use independently. DD still adores her giraffe and I have no plans to take it away, though we have talked about him staying in her room once she turns 3.
Maybe there's an alternative option 3 thinking about it.....something mid-way. Could you talk to him a lot in the daytime about how at night both he and Mummy need their sleep so they can be full of energy to play the next day. And explain that he can have his blankie in bed but that there will only be one and he can't have a new one in the night because Mummy is sleeping. Do you use a Gro clock or similar? Wondering if you could make use of that to reinforce that while it is night, mummy is sleeping so no new blankies. But incentivise that if he waits for lights on/sun up there will be a dry blankie waiting for him? I expect there will be some nights of tantrums but I think maybe you have to tell yourself your will is stronger than his, and I think he would learn quickly with a combination of consistency at night (the 'stick') and the 'carrot' of a dry blankie to wake up to. Could you even lock all the spare blankies in the car outside or the garage or something, somewhere it would be a real hassle to get them in the middle of the night if you felt tempted? If he wakes I would just tell him from outside the room (if possible) that Mummy is sleeping, he needs to sleep and that there will be a dry blankie when the sun comes up?
Do you think something along those lines could work?