I've done a complete 180 on this after our recent bad run of form but I don't think he's old and past it he's 30 after the January window, honestly I was for it last year but we really need some young blood in midfield or right back, preferably players who will put themselves about quickly and get stuck in.
Kimmich does neither when it's abundantly clear what we really need most is some pace energy and physicality in the side, I'm not sure we should go for him even if he's willing to join for a pay cut as we need everything I mentioned.
Technically and positionally there's no real weaknesses with him he'd probably do a job and adapt perfectly to Pep's tactics, he'd likely fit in to any system well but I'd rather focus on our weaknesses urgently with much younger targets who fit the strengths I mentioned.