whats wrong on sending btc twice or many times from same address , someone told me that the publickey point which starts with 04 is shown while transacting and thats bad for security of the account
There is no ''account'' if you are using non-custodial wallet, and security is not affected at all with sending coins from same addresses, but maybe privacy can be affected, if you are not doing good address/change management.
Reusing addresses for receiving coins can be even worse, that is why it's recommend to generate new address each time you want to receive payment, unless it's unique donation/payment address.