This is inaccurate. Regardless if you are using the mobile version of Electrum and its desktop wallet; you still have the options to manually change the transaction fees (sats/vbyte) by manually typing it or just simply using the slider. Also, it would be much better to check [1] https://jochen-hoenicke.de/queue/#0,24h to determine the least amount of sats/vbyte when broadcasting the transaction.
You are not getting it completely right. If it is electrum on computer, definitely you are right, you can edit the fee by also typing it, you can even edit the fee to be 1 Satoshi/byte. This is why electrum desktop wallet can be used to even consolidate. But on mobile electrum, you can although still edit the fee but you can not edit it by typing the it, it only gives five editing means which you can see in the below diagrams. Like the mobile electrum, fees can not be edited by typing it. 
