if you are not going to be client based (react, angular or vue), then Razor pages is probably a better match than mvc. it is getting all the new features (MVC is mature). Another advantage of razor pages, it will be more similar in design to your current technology.
if you need a more desktop like experience, than a client framework may be desired. the main disadvantage of client frameworks, is that they change often. a 10 year lifespan will require many framework updates. you will need the discipline to migrate to newer version at least once a year.
our main react application is 6 years old. Our main lesson, is to limit dependency on 3rd party npm packages. to stay current you need the packages to stay supported. WE are happy with our decision for react and would not change.