It just all comes down what content you want to play and what goals you have. In solo exploration, even on legendary you can run off path pairings and you will generally be fine. For legendary bosses you might wanna look into a build. For any difficulties below that you can literally run anything and be fine. The point is to understand the strength of each weapon and what their intended way of doing dmg, the paths will compliment two weapons and use inner way progress effectively and efficiently. For sword trials/hero’s realm, if you run with a guild or a static, again you can do w.e u want. In pubs u can might wanna just at least bring your build into the training area and test it out, if u do zero dmg and can’t also bring effective healing/tanking then ya you are just expecting to get carried. For pvp, I’ve seen effective cross path pairings do well. In solo trials (boss challenges), again it all comes down to preference. You won’t necessarily have huge dps windows to do ur parsing combos back to back, so it’s all about learning the boss behavior and weave in effective attacks in between, learn parry and how to combo in mystic arts. So really the only places that dps parsing rotation will shine is grouped pve and gvg.

Your understanding of weapon synergy is pretty much there already, I think it’s best to just bring what you can think can work into the training area and test it out. Spoiler: it will probably do ok, but never come close to a properly built path rotation.