When I sent my friend the test with .0001 BTC he received .0000927 BTC (around 7.3%) so going by his math, when I send him 0.3 BTC ($30k) there is going to be a transaction fee, and when he moves it out of his wallet there is second transaction fee, therefore he believes that he will receive approximately .26 BTC ($26k in the end).
As I said in my previous post, the transaction fee doesn't depend on the amount of bitcoin you send. In the other words, it's not that you pay a percentage of sending amount as transaction fee.
If you make a transaction to your friend with the same fee rate as your previous transaction, your friend will receive 0.2999927 BTC.
Even if you set the fee rate to 10 sat/vbyte (which is
now much more than enough), you will pay less than 2000 sat (around $2 worth of bitcoin).
Don't worry about the fees.