Romeo Lavia to be Casemiro's backup, Southampton might go down so it would be much cheaper. Only 19, huge potential.
At CB, Bella Kotchap looks like he has big potential, strong and fast and physical. Only 21.
Anel Ahmedhodzic for my Bosnian bias shout, but he's great in FM and has been great for Sheffield United since he joined and is clearly far too good for the Championship (but most of his time has been a RCB of a back 3, and in classic Bosnian fashion he is tall but lanky and technical rather than super physical. But has huge potential as a ball playing CB IMO. Only 23 but genuinely has huge potential.
There are actually a good amount of options we could go for in these 2 positions to replace McTominay and Maguire basically that would help us out and be logical eventual replacements for the 2. Always important to have a good blend of youth and experience, and for these 2 specifically, definitely need younger with big potential who could come in to cover for Casemiro and Varane when necessary and learn from them, and take over in 3-4 years.