I thought that someone can steal your coins only if they hack the wallet, have the private key, the wallet backup and the password.
That's correct.
I never thought that someone can just block coins in the blockchain or sniff a transaction somehow to end up with the coins you send.
That's not possible.
I would recommend you to stay away from such low value coins - especially master node nonsense.
The majority of them (probably 95%+) are a pure scam.
There are funnier ways to lose money, no need to
invest in scam projects.