I dont think he is... The story shows him swinging a sword that has its own gimmick and Zoro is trying to get used to it...
After that training, the sword still does what the sword does and Zoro is no different, he changed in no way.
The difference is Enma gathering haki cloud vs it not gathering haki cloud, a little bit more AP bcs of the sword, not bcs of Zoro.
Another difference is fire cutting, useful when facing the fire, useless when there is no fire, nothing but circumstantial convenience...
There is no confirmation about him not being able to attack that far, he wanted to KO Pica and he needed to get close to him because he cannot corner him from half a country away... There is no CoC-specific effect, Oda is just teasing it for future use.
The only difference between FMI Luffy and post WCI Luffy, after several extreme diffs is FS which he cant even use properly and Zoro without a single extreme diff is supposed to be significantly different? Like hell, I dont know why you buy into that... Zoro was always strong, he isnt inventing gears and learning hakis every arc, he isnt ineffective like Luffy...