My personal tips for the universal challenges [Endgame spoiler alert]

[Michaecola]

1. All spell buffs on yourself are ineffective. That also includes potions. Synchro, spellcraft and boosts are still effective. You cannot cast buff on your familiars.

2. For classes: Sage = battlemage > Cultist = Builder > Breeder = Student = Spellslinger .
2.1. You cannot add any buff on your familiars, so it will be much weaker than normal, makes breeder not ideal. Your study speed is low without exp catalyst boost, it will take forever to level up any elements even with student buff. Spellsinger is close to useless since you really don't have many spells to cast at all.
2.2. Builder and cultist will be slightly helpful, without storage buff, builder will let you add a couple extra level to all your furnitures. Your max corruption with max enhance is lower than 10, so you will take hefty punishment, but plentiful ritual is really helpful.
2.3. Sage and battlemage are self-explanatory. Any improvements to your battle performance is helpful.

2. If your primary element does not include death, the essence production will be miserable. You may need to use poison + water synchro to improve sewage output.

3. Same goes to your monstium income, so equip soul stone when farming.

4. Time element is completely useless in this run when most of the spells are buff/debuff. Includes delayed bash, the only offensive spell in time elements. So be careful, same goes to poison element. You cannot inflict wet, chilled, frozen and grounded, so earth, water and electric attack spells will be less effective.

5. Your study speed will be extremely slow (would took month to max non-primary elements), so the initial level of your elements are basically permanent. So consider your transmute option when picking primary elements. Also skip student class.

6. Armor is extremely helpful in this run when the hardest bosses are aberrant abomination and Lytha. Aberrant abomination attacks you rapidly with low attack, so armor will block most of the damage. And for Lytha, she don't use holy element, so all you need to do is perma-cast antidote, and manually cast knockout to impending doom.

Any additional ideas/tips will be brilliant.

[Rafeh]

For me, the first stage of the universal challenge came out even easier than the primary challenge on the death+space build. After all, with no buffs, you only need to go through a secret prison, which means that the big bang only needs to be brought up to 1m damage. I used the builder class to quickly increase the maximum mana reserve to the point of using a big bang, before using nova. When using the ritual for resources, I was just out of the fight, and I had to constantly switch its activity to transmute. Before the battle with the director, I farmed armor with a shield for a couple of minutes (increased them by about +5), then in a maximum of 15 minutes I got a +10 synergizer and a +7 staff, 5 minutes and the secret prison was passed.
P.S. I know English very poorly, so I translated over the Internet, played with localization, so I don't know the original names of the locations, spells, and tabs, but the translator could have translated incorrectly. I apologize in advance for possible errors in terms.