It's definitely easier with a contrroller because it's a twin-stick shooter at heart, you got the left trigger for the grenades and the right trigger for the dodge roll, and you can use either the right stick or the face buttons to shoot. It's still fundamentally hard though.
For those who find the game way too hard (and I can't fault them as I'm the saame, the game is super difficult), for an easy copout, you can use cheats and still see the good ending by using the backer menu.
For cheats:
On the main menu, hold LT(L2) + Left + Y (Triangle) and press Start.(Options) while holding the huttons.
With a keyboard, hold Q + W + Left and press Enter while holding the huttons.
For backer menu:
On the main menu, hold LT(L2) + Rigjt + Y (Triangle) and press Start.(Options) while holding the huttons.
With a keyboard, hold Q + W + Right and press Enter while holding the huttons.
On cheat menu enable whatever you want (including the fixed seed so you can practice and learn the patterns if you want).
By selecting Backer #7 you can see the good ending even if you cheat.
By choosing level "The HQ" in both menus you can also cut short on your run time if you just wanna see the ending.
Source:
https://www.trueachievements.com/forum/viewthread.aspx?tid=1219688 I don't care about achievements anymore (except maybe in Genshin) so I don't mind never being able to clear everything legit, but I hope it helps.