You like cerebral mysteries then. In which case I recommend
Sherlock
Foyles war
Bletchley circle
Life on Mars
Ashes to ashes
Cracker
Criminal minds
Mindhunter - basically the "true story" of his the behavioural unit featured in criminal minds came about. Fascinating.
Top of the lake (amazing but a tough watch)
Columbo was arguably the first of this type and I think still stands up well.
Broadchurch - I think people have forgotten how good this was especially the first series.
Unforgotten - I agree is an AMAZING series.
Whitechapel is very good, I've been unable to watch again though for personal reasons (I have OCD too and it's a bit too close to the bone for me at the moment, when I'm doing better I'll be able to watch again, by which point it'll probably be unavailable!)
Law and order can be a bit hit and miss on this score, criminal intent was the best version. Especially the ones with Vincent d'onofrio who I think is a HUGELY underrated actor.
Bones is a bit more quirky you'll either love it or hate it
White collar - I adore this show! But it may be too light for what you're looking for. But Matt bomer 😍😍
Person of interest - again a bit more quirky with the sci fi elements but I loved it.
The mentalist - I loved! But it's not to everyone's taste.
Perception - ditto
Numbers - I loved at the time but it seems really dumbed down considering the premise now.
@cakeandmarshmallows I used to love silent witness and started watching the old ones on the tvplay app - they're awful! Sam Ryan's always "missing" stuff she's not a genius she's bloody incompetent!