There are Teardown and X-Ray decals available from dbrand which were created in partnership with Zack from the JerryRigEverything YouTube channel and accurately represent the internals of the phone. They can attach directly to the back of the phone and there is also a case available.
Teardown: https://dbrand.com/shop/limited-edition/teardown
X-Ray: https://dbrand.com/shop/limited-edition/x-ray
I've got one on my S24 Ultra and love it. Personally, I prefer to have the decal directly attached to the back of the phone with a clear case on top.