I really don't agree with: get stronger must also have world get more difficult. This is how you get scaling difficulty, where you never feel like you're going anywhere, because every upgrade is made pointless by enemies just becoming more dangerous in turn.
Bullethell rogue likes like vampire survivor are getting it pretty right in my opinion. Just have the chance to get ridiculously powerful, but take a bunch of tries. Then add in Hades way of not ending the story with your death and failure, the nemesis system which is sadly patented and you'd have a fairly ideal game where some things will inevitably kill you, but you will get better and the small stuff will only get you still, if you are not paying attention.