head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Competitive PvP
Arc System Works' Dungeon Fighter spinoff where an MP meter turns specials into a resource economy.

Execution · Grand Arena
A tag-team crossover fighter pitting Street Fighter's cast against Tekken's under Capcom rules.
DNF Duel leans Execution (Competitive PvP); Street Fighter X Tekken leans Execution (Grand Arena).
Street Fighter X Tekken leans a little harder on execution, though the gap is small.
DNF Duel
MP skill combos are lenient but conversions still need hands.
Street Fighter X Tekken
Tag combos and juggle timing demand practiced hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
DNF Duel
White-damage pressure and Awakening baits drive human yomi.
Street Fighter X Tekken
Human mixups and tag baits require adaptation
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
DNF Duel
Deterministic systems throughout.
Street Fighter X Tekken
Deterministic aside from negligible elements
Street Fighter X Tekken leans a little harder on optimization, though the gap is small.
DNF Duel
MP economy management is the distinctive solvable layer.
Street Fighter X Tekken
Gem loadouts and team synergy add a builder layer
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.