mobility stats are here.
Grounded Mobility
Walk - 0.66
The 2nd worst walk speed in the game, second only to Incineroar, and lower than Jigglypuff.
Initial Dash - 1.58
The 3rd worst initial dash in the game, third only to Dr. Mario and Steve, and lower than Olimar.
Dash Speed - 1.55
The 68th-69th fastest dash speed in the game (tied with Min Min). In-between Bowser Jr. and Wolf.
Overall
Very poor ground mobility stats, one of the worst in the roster.
He NEEDS to utilize Crouch Dash at all times in order for him to execute his gameplan effectively.
Aerial Mobility
Air Speed - 0.89
The 78th-79th fastest air speed (tied with Byleth). In-between Banjo and Incineroar.
Air Acceleration - 0.01/0.03/0.04 (Base/Additional/Max)
The 82nd-84th fastest air acceleration (tied with Ganondorf and Little Mac), effectively making it the 6th-8th worst air accel in the game.
Only 0.005 higher than the Shotos, who sits right below him at 85th-86th.
Fall Speed - 1.7
The 27th-29th fastest fall speed in the game (tied with ZSS and K. Rool). In-between Snake and Cloud/Lucario.
Fast Fall Speed - 2.72
The 28th-30th fastest fast fall speed in the game (tied with ZSS and K. Rool). In-between PPlant and Cloud/Lucario.
Gravity - 0.108
The 13th highest gravity in the game. In-between Incineroar and Bowser/Diddy.
Overall
Aerial mobility stats are also very poor, having Shoto level air acceleration, but by far the worst air speed of the FGC group.
He falls fast from the ground, which is good for him since Kazuya wants to stay grounded as much as possible, although it does have the side effect of making him even more combo fodder.
Miscellaneous
Weight - 113
The 8th heaviest character in the game. In-between Charizard/Incineroar and Piranha Plant.
Jumpsquat - 7 (Meshima says it is 6, but others reported it to be 7)
The only character with irregular jumpsquat frames, being 4 frames higher than the rest of the cast.
Traction - 0.115
The 29th-30th highest traction in the game (tied with Fox).
Traction stats are unimportant due to everyone in Ultimate having high traction.
Tough Body - 14 KB Units
Not as high as Bowser's 19 KB units, weakened further by his much lower weight in comparison to Bowser.
Refer to Thinkaman's post above for more info.
Overall
Honestly, terrible stats across the board.
Has mobility stats comparable, and even worse in some areas, than Ganondorf and Incineroar.
Very high weight and fast falling speeds gives him good raw survivability and landing opportunities, but also makes him one of the easiest characters to combo in the game.
Combine all of this with his poor startup frame data and frame 7 jumpsquat, he feels like a SSB4 superheavy in Smash Ultimate.
This kind of shows how incredibly important and crucial Crouch Dash is to Kazuya's entire character design.