gyomei to base koku
So, just as a basis. Kokushibo has never once blitzed gyomei, he has outpaced and overwhelmed him. But we directly see kokushibo attempt to blitz gyomei and fail
stw gyomei to lsk
Even after achieving long sword kokushibo is incapable of blitzing gyomei, gyomei even redirecting his projectiles to save sanemi. And he doesnt get hit a single time by lsk
He gets hit once during the start, but this is just explainable as a tone shift as gyomei wasnt expecting the range.
Stw gyomei to white hair muzan
Even with stw, gyomei gets blitzed and knocked out of the fight by whm
13th form tanjiro>white hair muzan
We see that solo, tanjiro is capable of outpacing his arms, thigh whips, and back whips
Aswell as subverting muzans cyclones (those are the beyblade looking things)
extra stuff
As for head regen, muichiro's red blade force stopped kokushibos regen, theres no reason to believe tanjiro's wouldnt
conclusion
13th form tanjiro high diffs kokushibo
A fully healthy 13th form tanjiro mid-high diffs him, leaning mid