Firstly, one way we could impose a soft limit is that the more abilities you have the less effective each one is. i.e. the dash length decreases with more abilities, or double jump doesn't go as high. Also if the idea I had earlier about having Demonic and Angelic specific powerups, we could do the slider which changes the effectiveness of certain abilities depending on the others you have.
For certain abilities, we could do a double jump similar to monarch wings in Hollow Knight. A Golden Feather in Celeste but on cooldown, or a one-time use item. Something like climbing claws in Terraria which let you jump onto the same wall/ slide slowly down walls. In that same vein. Something that lets you sit in a certain place on a wall (like Celeste's grab, but you can't climb up and down). A super dash like Crystal Heart. A slow-fall ability, like the potion effect from Minecraft. Depending on how we do health, a regen ability that has a cooldown. Something that activates when the character is about to die and moves them out of danger but is one-time use (i.e. you're about to fall into spikes but a temporary platform spawns under you). A high jump similar to Kirby's up b in SSBU, where you gain a lot of height quickly, but then drop down quickly if you don't grab a ledge. A damaging dash that allows you to indirectly attack enemies (like a fire spin dash that can damage enemies in the way).
Firstly, one way we could impose a soft limit is that the more abilities you have the less effective each one is. i.e. the dash length decreases with more abilities, or double jump doesn't go as high. Also if the idea I had earlier about having Demonic and Angelic specific powerups, we could do the slider which changes the effectiveness of certain abilities depending on the others you have.
For certain abilities, we could do a double jump similar to monarch wings in Hollow Knight. A Golden Feather in Celeste but on cooldown, or a one-time use item. Something like climbing claws in Terraria which let you jump onto the same wall/ slide slowly down walls. In that same vein. Something that lets you sit in a certain place on a wall (like Celeste's grab, but you can't climb up and down). A super dash like Crystal Heart. A slow-fall ability, like the potion effect from Minecraft. Depending on how we do health, a regen ability that has a cooldown. Something that activates when the character is about to die and moves them out of danger but is one-time use (i.e. you're about to fall into spikes but a temporary platform spawns under you). A high jump similar to Kirby's up b in SSBU, where you gain a lot of height quickly, but then drop down quickly if you don't grab a ledge. A damaging dash that allows you to indirectly attack enemies (like a fire spin dash that can damage enemies in the way).
Hopefully, some of these are helpful.