4.5 is the hard cap, 1.9 billion is the original issuance of 40 per block for the additional issuance. After the halving, most of it is sent to the black hole. The kitchen explains that the contract cannot be changed. After the halving and reduction in volume, all remaining additional issuance is sent to the black hole, so the volume is very large, but you just need to know that the actual total amount is 3.66.