He was available for the vast majority of last season and only started 19 league games, and didn't start the CL final despite Thiago and Fabinho having one fully working leg.
Thiago started 5 games more than him last season. Pretty clear Thiago and Keita were being rotated, with Thiago first choice of the two. It's not surprising Thiago got the nod for the CL final, though with his injury in the warm up Keita probably should have started.
His availability last season was good. Possibly because of the rotation. He's only missed 5 match day squads in the last 9 months, one with illness, two were League Cup games during AFCON, one an early round of the FA Cup with a weakened side (Ox, Jones, Tsimikas, Origi etc played). So that's 1 game missed through injury since early December.
He's been available and he's played almost as much as Thiago in 2022 who I think most would agree is one of the first names on the team sheet when fit. Making out he's not trusted to play is wide of the mark.