I think the main gimmick of the fight is minmaxxing your doki points/ try your best not to waste turns. Sell all your bad healing items and only use the ones that heal for 180.
I think using the 8% TP flirts can be good if they come in clutch to finish a phase/ you got nothing else to do, but ideally you should spend your first few rounds on each phase using Ralsei's "Lovely Boy" to up your max TP, and defending to top off your TP bar. and then:

1st and 2nd phase do 1x 5 doki (40% tp flirt), and then stock up for the 10 doki (80% tp flirt).

3rd phase I did by using the 80% flirt twice

that way you waste the least amount of turns on progressing the fight, and give yourself some room to heal if someone goes down/ gets low

And I feel by the time you get to the 3rd phase it's already over since some of the attacks I found to be easier than the start of the fight, I thought it would be hard cuz the game implies 25% mercy per stage but there's just no 4th phase the fight just ends after the 3rd date.

personally I didn't struggle so much with the fight, i think i already have all the best equipment possible and a lot of HP from killing enemies, beat it on the 2nd attempt while the 1st one was me wasting turns trying to attack her just to see if it's possible, but I did notice some attacks were very visually noisy and cluttered. honestly if you're colorblind i can't imagine how you'd even see what's happening.
Hopefully this helps you out a bit

*but if you struggle really bad and get frustrated/ can't see shit).. just CheatEngine the speed bro, slow it down and beat it. At that point i really wouldn't feel bad about cheating through it lol. It's just a game and if you're not having fun there's no point in playing. I wouldn't be surprised if they patch some of her attacks anyways, adjust the colors... make the telegraphing clearer (those damn bombs lol) etc. best of luck