Everybody is speaking about MARA, but is really safe?
You go on first page and say enter your transaction hex without any identification.
Even with this issue of unknowing what is happening when you submit, if everything is true about stealing, why they do not steal from everyone? There are milions of transactions every day.
If this was the case, nobody was using bitcoin anymore...
I think you need to learn how transactions signed and why only certain ones can be cracked.
In short, "millions of transactions every day" don't use low entropy private keys. There is no way you can steal them using modern equipment in any feasible way.
There is no special "identification" needed to submit a signed tx to a blockchain.
It's well known what happens when you submit your tx.