One week>why Oda spend endless time with those side characters😡😡
Next week>why Oda dont give more panel time to the side characters😡😡
This happens because the first problem is directly connected to the second problem.
The first problem happens because Oda wastes time on characters that are either completely pointless (e.g. Urashima and Fukurokuju) or unnecessary (e.g. 1/2 of the Scabbards). All these extra unnecessary characters bloat the arc up and make it more difficult for Oda to effectively distribute panel time.
This leads to the second problem which is characters that readers have been looking forward to for years not getting enough panel time. Characters that people were hyped for like Jack, King and X Drake have had little presence. Jack in particular was hyped up back in Zou Arc to be a big deal with his inevitable rematch with the Dukes being something that folk were looking forward to and all that happened with this setup is that it got mostly off screened thus resulting in a disappointing payoff.
So yes, Oda is simultaneously giving side characters both too much and too little panel time because he allocates too much time to characters that no one cares about and too little panel time to those that readers were excited for.