~snip~
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. ~snip~
To be more precise, the number of editing means of a slider depends on what type of method you are using (e.g., ETA, Mempool, Static).
Mempool --7 slide option
Static -- 12 slide options
ETA -- 5 slide options.
I would still prefer to use the Mempool though and manually check the current required sats in order for my transaction to be included in the next block. As of now the required least amount of sats/vbyte is around 40 sats which is close to the 5th slide in mobile version.