I can see us signing either a younger CB to take over the spot long term or a stop gap. Not really a contradiction, it's more of two different strategies and it's up the board to decide if they want to get a older CB which will open up space for THB and E. Garcia or get someone who's ready now and have pretty much a decade left to give at the highest level. My response was to your post about that we should make our young CB's a priority is that I think we should get an older CB instead of signing someone like Upamecano if that is the case.
One thing is clear though, we need to sign a CB either if you like it or not. A new right footed starting CB should be our main priority. There is no way we're going to challenge for both the title and the CL with our current CB's, only Laporte and Fern are good enough on current ability and Fern should only be a backup this season due to his age
My prefered option would be to get someone like Upamecano, Konate or even Skriniar. Complete CB's who have much left to give. But I can also see us get an older CB to challenge for titles short term but also to ease in youngsters. One thing is for sure though, Otamendi and Stones are finished as consistent starters and starting THB born 2002 or E. Garcia born 2001 week in and week out would be to put too much pressure on them. Their time will come, there is no hurry