is signet  not testnet

I want to ask how to mine the test coins, SBTC, on the Bitcoin Signet network.

Can I mine test coins? I have some mining machines.

The same mnemonic generates two addresses on the test network: tb1pfscdjh8dkqy98gp0xkudrkx88zwslsvd32z60d9nhpm343rewsmqf55g7q and tb1q84jq2rq4jdf8nauum7haneseaqmg89zj944x5k.
It's easy to receive test coins at tb1q84jq2rq4jdf8nauum7haneseaqmg89zj944x5k, but tb1pfscdjh8dkqy98gp0xkudrkx88zwslsvd32z60d9nhpm343rewsmqf55g7q cannot receive them.
Why is this?
How can I obtain Bitcoin test coins?

After I converted the image file to buff, it was 2566. This operation was correct.
However, after serialization, cbor changed to 5889.
The correct one after cbor should be 3542.
Why is mine 5889?

Thank you all for your help.
I get it, except wait for the fees to drop low enough.
There is no other way. . .

To put it simply, I developed a mint inscription tool, and then they donated about 5,000 transactions to me, and each transaction was (2000 Satoshi).
Now I find that I can't get these Bitcoins because I need a lot of gas. This is a cost I cannot accept

I have a Bitcoin wallet with a （bc1pt*******） address and received tens of thousands of small (2000 Satoshi) payments.

How can I get the lowest gas transaction balance?