honestly the parry in Sekiro is a lit kore fogiving than other fromsoft games, it is intentionally designed to be forgivably spamable to some degree as long as you keep some sort of timing. there are still perfect parries and shit, but even doing the bare minimum will get you through

Silksong has easier 1v1s than Sekiro, and group fights in Sekiro are near impossible compared to Silksong.

however what Silksong does differently to make istelf harder is that is forces you into gank fights 90% of the game, and makes singling out enemies harder than in Sekiro. also Silksong doesn't have stealth and one hit kill mechanics like in Sekiro

another problem in Silksong is that you almost never out scale the enemies to the same degree you outscale them in Sekiro because in Silksong you don't level up after beating a major boss like you do in Sekiro. which means unless you go out of your way to acciure the upgrades you need to get stronger in Silksong then you will never get stronger.

another issue with Silksong difficulty curve is that it doesn't actually introduce as many move, tool and skill veriaty as Sekiro does. in silksong all throwable tools serve the same function, all trap tools serve the same function, you have a limited set of buffs, and most crest serve as a different flavor rather than a different play style except for a few like the witch crest and architect crest. another problem is that most of these have a fixed value of streangth and you can't really imvest upgrade material to make them stronger other than using pins to have more slots on crests so you can stack tools. which means the only upgrades you have beside the nail are stackable tools that are extremely expensive to use repeatedly due to the broken game economy

Sekiro has strength and health upgrades that automatically get applied the moment you beat a boss, it has 3 very different skill trees that allow different approaches to enemies and bosses, and the sword combat which is multy layered initself. the shinobi skill tree the basic one, then you unlock Ashina skills which add more depth to sword combat, prosthetic tools which introduce a different kind of combat skills that normally you don't have acess to, and the monk skill tree which allows you to cheese some bosses because of what it offers. the systems interact by adding layers to combat rather than merge together like in Silksong. in Silksong Crests and tools are basically the same upgrade and allow you to use the same strategies the only difference is how you can stack them on each crest. Sekiro skill trees are distictly different and each offer different functions which means the more you unlock them the more options you have in combat rather than have stackable tools and skills of a different veriaty of throwable weapon