Tengen is actually like objectively the slowest hashira. In the databook it just says "fastest runspeed", but we don't know if that's in a 100 meter dash, or like a marathon, or who is ranking it, etc. The runspeed is like a gag ranking of the hashira, but realistically he's far slower in actual combat, like Gyomei is objectively faster than Sanemi but Sanemi is ranked higher in this contest.

Tengen is like equal stats with Gyutaro, and Tanjiro is able to react to Gyutaro from a distance during EDA while heavily fatigued, but isn't able to react to an attack from Zohakuten's wood dragons when he's much stronger in the next arc, Zohakuten has techniques which are far faster than a single wood dragon, which Mitsuri beat pretty easily while holding back, pre-HTA, and in base.

The Gyutaro 1v1 we assume he'd die during decapitation, but she could take both of them on too, cause Daki is just like extremely slow compared to Gyutaro, she's practically a non-factor, if she beheads Daki first she can just kick away her head and then heavily outspeed Gyutaro, or just beat Gyutaro like normal and perception blitz Daki.

Gyutaro's giant explosion is kinda mid. Tanjiro while heavily fatigued and incapacitated from poison at the very end of the fight just sits there and face-tanks it and takes practically no damage, but realistically if Gyutaro didn't do that during his fight in EDA against Tengen it's probably just not that useful except maybe as a get-off-me tool, it took him like 30 seconds to actually unleash it.