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

Execution · Twitch Chaos
Kart-racing control with item RNG swinging family-friendly races.

Execution · Twitch Chaos
Kart racing execution moderated by item randomness and learnable track routes.
F1 Race Stars leans Execution (Twitch Chaos); Sonic & All-Stars Racing Transformed leans Execution (Twitch Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
F1 Race Stars
Kart handling and boost timing decide clean laps
Sonic & All-Stars Racing Transformed
Drift timing and transforming vehicle control reward practice
F1 Race Stars leans a little harder on reads, though the gap is small.
F1 Race Stars
Human racers feint and time item attacks in multiplayer
Sonic & All-Stars Racing Transformed
Human racers add light positional mind games
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
F1 Race Stars
Item rolls swing positions like any kart racer
Sonic & All-Stars Racing Transformed
Item rolls regularly upend race positions
Sonic & All-Stars Racing Transformed leans a little harder on optimization, though the gap is small.
F1 Race Stars
Track shortcuts and KERS timing are learnable edges
Sonic & All-Stars Racing Transformed
Track shortcuts and drift-boost routes are learnable
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.