It would be to level up all skills to max in one day without mastery, it can be any day but you have to level all at once without gaining xp in any way before that day, that would mean that the only way would be gaining money with actions that give no xp like tilling and artifact spots so clay farming... Yes it would be tedious but and yes you would need rng if the world isn't on legacy mode cuz maybe the only way would be books, but c´mon it isn't lie no one would like the challenge??

emmm……I have a suggestion about this：change the rules to a total of all skills reaching level 10

(give a few examples:①Farming 2.lvl+Mining 3.lvl+Foraging 3.lvl+Fishing 1.lvl+Combat 1.lvl ②Farming 2.lvl+Mining 2.lvl+Foraging 2.lvl+Fishing 2.lvl+Combat 2.lvl)

It means you can harvest crops，care for animals，fish，kill slimes，mine ores and improve Forageing on Green Rain Day.Also,you can dig up the winter roots/snow yams in winter and sell them in order to buy books through Bookseller.In my opinion, this kind of challenge is more interesting and less time-consuming.>3<