Oda made a very long Arc to show how Sanji is more about Kindness & Heroism & Caring & Cooking Skills but his Fans want to desperately draw him as a pure Fighter who can rival Luffy & Zoro
His Father & Siblings called him a Weakling, what more do you need?
Luffy & Zoro are the Main Fighters of the Crew & meant to surpass everyone
The rest of the crew have a job to fulfill but they also can fight of course & Sanji happens to be the Strongest of them, that's all
I mean, Luffy and Zoro can be the main fighters, like they were pre time skip as well.
Sanji can be the third strongest and a monster compared to everyone else as part of the M3, like he was pre time skip as well.
I like how people read WCI and can acknowledge the bit that you talked about, yet remain oblivious to the fact that at the end of WCI, Oda offers an answer to maintain the M3 with a Sanji that is not as focused on training and combat as Zoro for example.
It's like the existence of the RS becomes apparent only to shit on Sanji for accepting it, but it's implications and purpose, we don't really want to acknowledge beyond that.