If you do not understand why every 5th is open. Then you need to learn this topic from scratch.
But in a nutshell, then when we hit the ceiling of 60-64 bits. The creator of the puzzle specially made a small transaction from every fifth address, thereby opening public keys for these addresses for public access. A public key search is a completely different search than an address.

You will not show the found private key, someone else will. And if you find a private key from the address, which are still with balances of up to 115 bits. And you withdraw funds from there, then let's say the address will be available to addresses 64,66,67,68,69 bits within 5-10 minutes, because it is supported by low capacities. The 64th generally breaks through in a second if the public key is known from it!

And in general, in a puzzle, not so much chasing a prize, as more "measured by pussy". Who has more power, or who came up with the best algorithm. Some connect 800 processor cores with a terabyte of RAM per system.

Why not publish the private key from the address you have opened from this puzzle? We are not talking about other addresses, but about the addresses from the puzzle. What is the point of keeping it a secret if you have already withdrawn all funds from it?

There is simply no such address in the puzzle from which the funds were withdrawn, but the private key would not be known. Because if someone finds an algorithm for finding the next bit, then in a very fast time this algorithm is used by others and the private key becomes generally known. For this, this puzzle was created, in order to identify the current possibility, both technical and algorithmic, for the possibility of opening a wallet with a certain bin of the private key.