The second half of WCI starting with the Tamatebakko explosion was a disaster with the overuse of plot armor and plot induced stupidity in the Straw Hats' favor, the wedding cake chase, Big Mom and her daughters being clowned and mistreated and neglected so badly, the eternizing fight against Katakuri when Luffy should have died a hundred times, the Zeff issue being dropped, the cringeworthy and so convenient Zeus subplot, etc...
This made me drop One Piece for several months because I had enough, but I came back for the very end of WCI and beginning of Wano, still hoping that Oda would learn his lessons and do better for Wano.
I enjoyed the first part of Wano overall but several issues started to weight on the story such as Tama and her power, O-Lin's plot, the stupid BMP waterfall issue but it was less problematic than the Udon mini-arc with prison just turning to be a training camp for Luffy, and of course the Oden flashback which started well but became so bad with Oden being such a dumb and overrated character thrown into our mouths and underserving of the idolization he got, and him submitting to Orochi and Kaido and doing that stupid cringeworthy dance under the weak excuse of saving people while he was in truth allowing Kaido to reinforce his power and persecute Wano even worse.
And then happened the other disaster of Onigashima war, combining Dressrosa and WCI flaws but in even worse with far too much stalling, plot armor and convenience, bland or dislikeable side characters, utter lack of tensions and stakes, weak writing, etc...
This arc really did something to me and my appreciation of One Piece, there is a before and an after Onigashima for me. Now I am still struggling to find some excitement and surprises about OP.