All I have to say to this is we recently rebuilt our admin tools application and the team responsible have been all backend / devops engineers. Stack is React and GraphQL. Without having any real FE experience this team has been absurdly productive. Rewind the clock a bit and it would have been a nightmare. From this experience alone I can conclude that the complexity issue the OP is citing is mostly an illusion, assuming there's someone around who can help guide tech choices at the beginning. There's simply no way a team of non FE engineers could build this stuff so well, and so quickly, a decade ago.
Yeah, I definitely know this through painful experience, but historically library upgrades in non-trivial apps have always been difficult. It is what it is, and its the same in every stack.
