Most I've made before egg festival was a few hundred k, but that was through methods not really easily repeatable for most.
That being said, I still have some general tips for getting money by the egg festival (or my main tip just to skip it entirely, as it usually isn't worth it at all):
1. Since the ability to water and maintain crops after a certain number of them becomes very time/energy consuming, you'll generally have a limit of crops you'll reasonably maintain (meaning you don't need to make really absurd amounts of money). For example, most people will cap out at around 200 crops watered a day, and maybe a few more if you managed to get materials for sprinklers prior to the festival, which means you need 20k.
2. Your best bet is focusing on one method of moneymaking, as opposed to multiple methods. This is because as you focus on one thing and gain experience/levels and tool upgrades within that one field, you make much more money than what you were making to begin with. By doing multiple methods, you usually just keep both methods in the less profitable stage and end up hurting yourself.
So with those things being said, your two best options are either going really into fishing, or really into mining.
Fishing would entail trying to level up as fast as possible to begin with, then buying the fiberglass rod/bait and focusing on the more profitable places to fish, generally the river/secret woods when raining and mountain lake when sunny.
Mining would entail being able to get deep in the mines (ideally 115, but not 120) fast, then diamond/void farming, resetting elevator floors 115/105/95/0 for diamond nodes and big clumps of void monsters, giving a fair amount of cash per day even if you go at it very casually/aren't great at combat.
