Ok, after more research I have a theoretical view on the fees charged for investing in bitcoin with fiat from your bank account then returning fiat back to your bank account:
step1) buy BTC via bank transfer (no fee for SEPA)
step2) for holding, transfer BTC to safe wallet -> withdraw fee: 0.0005BTC
step3) deposit BTC from your safe wallet back to binance wallet ->
https://www.buybitcoinworldwide.com/fee-calculator/= 0.1 - 5EUR dependiing if you're in a hurry or not (assumption 1:1 as inputs and outputs)
step4) convert / exchange BTC to EUR -> 0.1% binance fee
step5) withdraw EUR to your bank account -> 0 fee
Concrete example based on initial investment as 1000EUR:
step1) buy BTC via bank transfer as 1000EUR worth -> 0.044171BTC
step2) for holding, transfer BTC to safe wallet -> withdraw fee: 0.0005BTC => 0.043671BTC in your safe wallet
step3) deposit BTC from your safe wallet back to binance wallet -> assume 0.0002BTC mining fee -> 0.043471BTC in your binance account
step4) convert / exchange BTC to EUR -> 0.1% binance fee => 0.043427529BTC to EUR (assumed same value as in step 1) = ~983eur
step5) withdraw EUR to your bank account -> 0 fee -> ~983EUR in your bank account
This means in order to have a profit you have to take care of the BTC/EUR ratio to cover the Binance trading fee (0.1%) withdraw fee 0.0005BTC and mining fee (~0.0002BTC)
Is this calculation correct? (the steps at least as the actual figures depend on the market trend and mining fees)
Another question, is there a limit to the amount you can withdraw from binance account per transaction / day / month as fiat?