Eternity in an hour
A potential solution to this could be to have special checkpoints that don't allow you to spend lives when you return to them, and so you always respawn with no rings. You would have to hit a normal checkpoint to regain the ability to spend lives to hold onto/regain rings on respawn. This gives the map maker control over when the player can respawn with rings, so that difficult sections of the level in which you can only have rings you collected earlier in the level can be made. If the player dies in this section of the level, they will always respawn with zero rings. This provides incentive to do well in these sections, as it's the only way to keep your rings.respawning with 10 rings if you die at zero rings... idk, you could farm with the lives scattered around the level, and if you reach to a level that was meant to be hard (with enemies or bosses), well... you may know the rest
Ideally, more checkpoints early on in the game would allow you to respawn with extra rings so that newer players can afford to take hits more often and learn from it, while much later in the game fewer checkpoints would allow for this, causing the player to need to rely on the rings they find in the level itself more often. Modders could also influence how difficult they want their level to be by what kinds of checkpoints they choose to place, and how frequently.
There would need to be a clear visual distinction between checkpoint types though, so that the player can tell at a glance even at high speeds between the types. This would also ideally be covered in the tutorial.