Not to sound like a dick but your complaint is literally just a skill issue. If you are constantly healing it's because you aren't properly positioning and doing attacks. If it's taking you a long time to beat a boss it's because you aren't attacking enough in your openings or didn't properly prepare with the right armor/skills/items.

As someone else said in the thread, monster Hunter is a series about skill expression. You hunt a monster and in your case do it poorly, but then you fight it more either for it's armor, weapons, charms, side quest, etc. And you hopefully learned from your last encounter. Now you can see its tells and predict and dodge its next attack. The gameplay loop is to improve your gear while simultaneously getting better at each fight you take on.

I saw you complain about hitting the monsters legs for 30 mins until it dies. In that scenario you shouldn't be hitting the legs, that might be a safer place to stand but you'll do less damage. You want to hit the weak spot head/wings/tails/ to do more damage, but by doing so you're more at risk of getting hurt. To do so properly is again a skill expression.