I think a hard mode would be wonderful if you felt like devoting the dev time. I'm not sure how much it would really take, but I think current endgame is maaaaybe fine? It's hard to say, I'm not sure how apparent the really broken stuff would be to someone that isn't trying to approach the game from that angle, but adjusting the endgame might not be a bad idea. The starting the game on your first playthrough is already fairly challenging, and cranking it up for the very end might just be in line with the intended narrative experience! I do think it's fine as is tho and hard mode is the preferable option here. Getting to trivialize end game stuff is the reward for meta-gaming, increasing difficulty too much could offput a more casual player. A hard mode however, presents a challenge for those who want it! You can get brutal outside of the fights too if u wanna script an event or two - like the landlord coming out at random overworld chance for a down payment on your rent, and taking all your money.
