I felt the same way - after a couple of months of playing Wordle daily, it shifted from "oh, this is exciting" to "okay, just going through the motions." Then I started testing math apps and stumbled on some really good stuff. Nerdle is your baseline, sure, but there are definitely more variations in that same style.
It really depends on what you enjoy more: If you're more into playing around with numbers, I'd check out Mathle - it works similar to Nerdle, but with a different focus on the types of operations. Then there's Waffle, which is more of a grid-logic puzzle with numbers, so less arithmetic, more combinatorial puzzling. It has a different rhythm than Wordle because you can try more things and aren't limited to just six attempts. For something completely different: If you're into text-based puzzles too, Semantle could be interesting - it's not focused on math, but it trains logic in a totally different way.
What I personally find wild is that a lot of these apps are free or at most have a small paid version for extra features. The thing with daily puzzles is that you don't get addicted to "just one more round" like with regular games - one per day, then you're done. If Nerdle-style stuff appeals to you, I'd check if the Nerdle store itself has other games from the same developer. They usually have multiple variations in their portfolio that work well together.