The absolute amount you pay as a fee needs to vary with both the virtual size of your transaction (which is based on how many inputs and output it has, not on its monetary value), and how congested the mempool is at the time of sending. Your absolute fee divided by your transaction size in virtual bytes (which Electrum will work out automatically and display for you) will tell you your "fee per vB", which determines how fast your transaction will be confirmed. If you put your transaction in to a block explorer like blockstream.info, the transaction fee field tells you what you paid in sat/vB, which is what determines how fast your transaction will confirm.

If you look at either https://jochen-hoenicke.de/queue/#1,8h or https://coinb.in/#fees, you can see the ball park figure of what fee you need to pay for a relatively speedy confirmation.