Right. When I've seen these kinds of efforts they seem to take one of two paths:
1. Specialized, monolithic systems. These try to do everything for everyone and usually end up devolving into the 12-month (or longer) release cycles. "Monolith" doesn't mean monolith vs microservice in this context. Just that the system is trying to be all encompassing. This is the norm. It rarely works well because it massively increases the cost for change (money, personnel, and time) even for what should be minor things (Oh, you need a custom report? We'll get it to you next year.).
2. Generalized, flexible systems. A document management system like you discuss would be one potential solution. These tend to be more data-oriented (sharing a common database or a common set of databases) with potentially custom front ends. The front ends tend to permit flexibility for the user, including generating their own queries and workflows. These usually work out better, but are not that common among mega corporation or government digitization efforts.
The former is easier to "sell". You get to manage a massive contract, it looks more productive than it is. The latter tends to be more grassroots, an internal effort. The former is highly visible, the latter is nearly invisible.
Related, people tend to overvalue work that appears difficult and undervalue work that appears easy. The second approach tends to make modifications "trivial", so the managers ask, "What are we paying you for?"