It’s a third choice signing really and not someone you’ve been linked with which is why I mention scattergun.
What are you on about, have you totally missed Koulibaly being consistently linked with Chelsea for at least the last 5 years every summer?
At the end of last season the club's unofficial media mouthpiece Matt Law reported that Chelsea have an 8 player shortlist for CBs and the plan is to sign at least two of them.
De Ligt and Ake were obviously at the top of the list for Tuchel and thus we've seen most rumors of the club being after those two, but it's been pretty widely reported Jules Kounde, Presnel Kimpembe, Jose Gimenez, Josko Gvardiol, Kalidou Koulibaly and Pau Torres have been heavily scouted and looked into as well.
Because of his age Koulibaly was probably not considered a primary target at first, but after missing out on Matthijs De Ligt and Tuchel obviously not being as keen on Jules Kounde as the previous board clearly were, I'd say Koulibaly is right up there. On current level I'd say he's probably the best of the bunch so I wouldn't complain if we ended up getting him. The age is of course a slight worry but if we could get 2-3 top class seasons and 1-2 years of him being more of a rotational squad option I'd say it represents great value.
After losing more than half our defence from last season we can't exactly afford to be picky and think
"either we sign the number one target or nobody". That's the kind of mentality you have when you already possess a very high quality squad, not when an overhaul is needed.