I want the game to be a grating challenge, though.
To be fair it is even on "Normal".
The first actual Companion Faction Quest is impossible for a low level character even with a companion.
There are many creatures that will stomp you flat and others that will stomp you and your companion flat as well.
Remember Lydia is more powerful because you have already adjusted the game settings before even trying them on normal.
If you dismiss her she will wait for you in the Jarl's Hall or if you have your house in Winterun she will wait there.
I do understand your complaint but the question you need to answer is "
What are you going to do about it"?
I reckon you are looking at:
- Change difficulty to normal.
- Dismiss your companion.
- Keep playing as you are.
Certainly it's not worth throwing in the towel over.
Bethesda have been making games for a very long time and before you discount something just because it wasn't the way you would have done it you may be pleasantly surprised if you actually stick with it and give it a go.
Azrael
The Nord with the Sword