and poetry-monorepo-dependency-plugin (1.0.6) depends on poetry-core (<1.7), poetry-monorepo-dependency-plugin (>=1.0.6,<2.0.0) requires poetry-core (<1.7).
And because poetry (1.6.1) depends on poetry-core (1.7.0), poetry-monorepo-dependency-plugin (>=1.0.6,<2.0.0) is incompatible with poetry (1.6.1).
So, because poetry-instance depends on both poetry (1.6.1) and poetry-monorepo-dependency-plugin (^1.0.6), version solving failed.