Yeah, collecting more souls basically made the lamp take more breaks :D I’ve changed that in v0.33 — it now dims based on time, not the number of souls collected.
There’s also an “Everburning wick” upgrade that keeps it at full strength longer and shortens the dimming, plus stronger range upgrades. Some of this was already in the works, so we ended up thinking along the same lines :)
A relic upgrade for lamp range sounds like a good option too. I’ll keep that in mind!