Both sides can talk through the standard Dataverse integration that BC already uses for customers and contacts, it only needs to be set up for the custom tables since Microsoft ships it just for the standard ones.
The idea is simple. A small extension in BC creates a mirror of the Dataverse table, then a mapping is registered that says which BC table goes with which Dataverse table and which field goes with which field. After that a job queue entry does the work, it wakes up on its interval, looks for rows changed in Dataverse since the last run, and brings them over. So changes arrive within a few minutes, not the same second.
Worth deciding early whether the flow is one way or both ways, because bidirectional brings conflicts when the same record is edited on both sides.
If instant is important and nobody needs to manage the link from inside BC, a Power Automate flow that fires when a Dataverse row changes and writes into BC is much lighter to build. Less control, but far less work.
Glad to help - follow up if anything is unclear.
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Regards,
Grigorios Mavrogeorgis
Business Central Consultant & AL Developer
Work: Gmsoft Limited
Blog: insidebusinesscentral
LinkedIn: linkedin.com/in/gregorymavrogeorgis