Why not? We could even have a reason that Sanji awaking his new powerup?
Bang speak about something with I want for Sanji since I hear it in WCi arc.
Sanji losing to Jack, thinking of himself why he can´t defend his crewmates, he need even help from them twice, he is exhausted and angry for not beeing stronger and that could be the moment where he awake hiis exoskeleton, his healing power increase, his fire power, durability and power. Finally he unlog his true potential, in that case no RS would even be need in future but if it would only even make Sanji stronger.
The same Sanji who get defeated by Jack can now match Queen or King, with a powerup, haki skills and his skills with he learn from Ivankov, why it wouldn´t be better for his character to go though the hard way?
If Sanji lose to Jack, I can see him awake his exoskeleton and true potential, it was like he was always nerfed, now awakeing his true potential would make him far stronger. Would like the concept, in both way Oda would handle Sanji good and also would hype the Calamity since the current Sanji is not weak, in my opinion he could match Doflamingo. Now imagine he awake his exoskeleton and we have a new monster alongside Luffy and Zoro. Would like it a lot if, as Luffy Sanji need to go the hell hard way, let be honest Luffy was a bunching ball against both Cracker and ofc Katakuri, yet these fight make him far stronger.
I hope the same for Sanji and all strawhats, going beyond their limit.