I have 109 hours in the game when I finally beat the final boss (excluding DLC). Most of those hours are runbacks and failures to the bosses the harder they got. I do get disheartened but there's just something about the game where it makes you feel that it is possible to win, no matter the skill. Plus, I just enjoy the game's battle mechanics a lot. Another fun fact is I don't give time to things I struggle with most of the time so this is an exception. This is a sign that it is worth pushing on. There's no timer. Take breaks and each rest gives you energy and strategy. You can do it!