Just because repo structure can relate doesn’t mean that such a relationship involves any properties of monorepo structure vs polyrepo structure.
Any messy code organization or dependency issue you can have in a monorepo, you can also have in polyrepos. Any automation or central controllership you can have in a monorepo, you can also have in polyrepos. Any scale-out chores or overhead work you can have with polyrepos, you can also have with monorepo.
The issues of monolith / poorly coupled dependency applications vs microservices has absolutely nothing to do with monorepo vs polyrepos. Neither option makes any class of tooling easier / harder to build or maintain. Neither makes conceptual organization easier / harder to get right, neither makes discoverability or cross-referencing easier or harder. That whole axis of concern is just fundamentally unrelated to the application monolith vs microservices question.
Any messy code organization or dependency issue you can have in a monorepo, you can also have in polyrepos. Any automation or central controllership you can have in a monorepo, you can also have in polyrepos. Any scale-out chores or overhead work you can have with polyrepos, you can also have with monorepo.
The issues of monolith / poorly coupled dependency applications vs microservices has absolutely nothing to do with monorepo vs polyrepos. Neither option makes any class of tooling easier / harder to build or maintain. Neither makes conceptual organization easier / harder to get right, neither makes discoverability or cross-referencing easier or harder. That whole axis of concern is just fundamentally unrelated to the application monolith vs microservices question.