Quick answer: the best farm is the hardest route you can clear consistently without frequent resets. Reliable completion beats a theoretical high-yield route that wipes.
Choose a repeatable route
Track completion time, wipe rate, and whether the route advances another unlock. Drop optional danger that does not improve those outcomes.
Combine goals
Farm while learning a main class, completing achievements, or collecting a needed subclass. This makes each run useful even when the currency result is modest.
Check live prices
Cealt costs and Robux exchange offers can change. Verify the lobby before making a purchase decision; this wiki does not preserve old promotional pricing as current advice.