Dumb transaction question (Bitcoin mining is very expensive)

[hidedocscom]

Hi Everybody,

I have a dumb question about mining my own transactions.
One month ago, I transfered my btcs using a old software and the fee for mining went with zero; So, four days, five days, six...  and nobody confirmed my transaction; So, I made other transaction with 5 USD to mining my transaction and invalidate older.
It's not right, I know, but I was desesperated.
After this day, I think about it everytime and one question doesn't go with my head.
If I mark my transaction on blockchain and confirm this 6 times, this transaction can be validated. What happen if I confirm 6 times a double spend or one invalid transaction with fake coins?
Imagine that if I pass for one exchange wallet this with zero fee and confirm for my own transactions and there, I change for other coin and withdraw.
Where is wrong my thinking?

Tks

[1715138349]

1715138349

[1715138349]

1715138349

[Cryptolator]

You can't have two transaction validated in a double spending situation. The one with the highest fees will be validated first and the second one would be invalidated.

[hidedocscom]

Ok. Thanks. If someone (miner) using a normal mining program and visualizer this transaction, the highest fee is processed first and the other is invalidated. But who is responsable to invalidate other transaction and kill it from blockchain? Is the own miner program? Somebody know?

[vh]

There is the mempool and there is the blockchain.   The process to add and reject transactions getting on the blockchain is done by all mining nodes (confirms).  The flux you are observing is mempool activity.