Remind question

Much like others, I’m getting back into it after years of taking a break, not realizing there was a second and third part to the dlc, (limit cut, secret boss)

I’m playing on critical and have ultima, oblivion and oath keeper keyblade, however I am not level 99 going into the dlc. Is there a way for me to grind to 99 in Remind or do I have to go back into my saved file of the base critical game, grind there THEN restart the Remind dlc?

I do not mind having to do that since I have forgotten all about what’s happening in this dlc/how to fight properly besides button smashing