Sekiro

Oh yea he's a major hurdle and skill check in the game. If you don't get the hang of parries by the time you defeat him - which you probably won't if you don't - you'll have a hard time beating the game. Once it clicks, though, the entire game opens up to you and Genichiro becomes one of the best bosses of the game and maybe even FromSoft games in general.

Elden Ring skills also, sadly, don't really translate over to Sekiro all too well since they have entirely different sets of combat skills in mind: whereas in ER you dodge and weave in attacks here and there, Sekiro forces you to stand your guard and parry attacks with the odd dodge sprinkled in there for unparryable attacks.

I can definitely recommend giving it another try if you're up for it. It's a really good game and my favourite FS game/Soulslike by a huge margin, only closely followed by Lies of P. It takes some time getting used to it, though.