the broadcasted transaction is done on a new laptop using new phone, sim, internet & hotspot.
None of this is needed. As long as the signing is secure on an air-gapped device so the keys can't touch the internet, it doesn't really matter what you do with the signed transaction. Copy it to an USB stick and broadcast it on your regular computer. Some people even post the raw transaction on Bitcointalk. That doesn't mean anyone can steal the funds.
Its a bit much really it blows my mind how extreme you have to be with safety.
There's no need to go extreme. I posted
my basics, which hasn't been contested in years.