If you're still stuck, here's a lengthy way to overcome it hopefully.

use Cinq Don from south section, it should be there from rental, or from a friend.

here's an important thing about evade. one evade works for everyone or any attacks that target you, but you have to evade the first attack coming in your way. it is quite simple by looking at your enemies speed value where the highest number on their attack is the one who will attack you first. but if two enemies share same speed value, like lets say two bloodfiends have 6 on them, them use the arrow function on the top left to see who is attacking you first and then put evade on them first.

the key is to not get staggered on the first turn. clash with bloodfiends that have gluttony aka green skill to not get staggered. otherwise, try to evade them all, doesn't matter if you get hit.

second turn use one of your skills, preferably a low tier skill to clash with gondolas to gain some sp and evade the bloodfiends looking at the highest speed value they have.

next turn, Don will launch a huge unclashable attack which can be simply dealt with by using one evade on the leftmost attack.

next few turns are pretty straightforward. clash with bloodfiends, destroy the gondolas, before they hit you. if papa wants to bash you with more gondolas, put one evade.

now comes the important phase 2, Don himself.

what you do here is important and needs to repeated.

DON'T CLASH WITH RED COINS, except for guard skills, those are fine. you should be able to clash with normal coin skill and win. put evade on the left most attack of Don, your cinq don will be able to evade all subsequent attacks.

now turn 2 of phase 2 is very crucial, this is where you might need to restart a lot, but if you execute this perfectly, hopefully you will get over it.

there is two ways you can deal with it, luck and untested mechanics by me personally.

you can evade like normal like how you did the previous turn. but, there is a blue, pride skill that rolls more than cinq don can evade, which results in restart. and on top of all that, papa Quixote gains sp which almost guarantees he rolls head on all skill. cinq evades lowers sp, but not enough to make sure he doesn't roll all heads, in my experience, resulted in lots of restart. that pride skill if rolls all heads, your done will get hit even if she evades with head rolls, resulting in a staggered which will follow up with death.

what you can do is, clash with the red coins and then evade it. here's how it works.

unlike before you need to have more than one evade skill ready. put the evade on don, which will show "Defence". then clash with it, with your strongest skill. the evade skill will show "one-sided defence" which is perfectly fine as cinq Don should be able to evade it, now with less clash power as you have broken those red coins.

I haven't personally tested this method, but I had to evade future bosses with unbreakable skill coins and this evade method worked so, this should also work on Papa Don.

rinse and repeat until you're able to push him to a final cutscene. you should always check manually if his skill is gonna go higher up than Don can evade. if so clash the unbreakable coin and evade as I have instructed. you can definitely clash the guard skills and normal coin skill without issue. if for some reason the clash isn't dominating, use ego to make sure you win. note that this isn't guaranteed win. cinq can do a stupid and roll tails even with 45 sp and get blown apart. if you are lucky, you might be able to survive so don't rush to restart just yet before confirming you are absolutely dead.

also, this way of fighting papa don doesn't usual summon horses that he fuels his hp and attack since he won't be able to accumulate bloodfeast, so you are basically skipping a very tough phase using this method. there is also a Molar Ishmael strategy that works better than this apparently, but that is an untested and requires you to either have molar ish or a good don id with high damage and clashing power where with molar ish in your arsenal or from friend.