Perfect explanation of the problem - and if I may suggest the solution is to carve some of those experienced people off as military do into a "training role" - where experienced people rotate off projects onto R&R and then onto training - creating a mini bootcamp that also has knock on benefits of building standards, tech stacks and tooling that "we have always been meaning to build".

Someone recently pointed out that we should learn more from how militaries grow and survive over the years - this is probably the biggest lesson.