I have been working with workflow for a long time in many systems and each one has it's nuance. I highly recommend a good testing phase and plenty of patience.
Recently, I ran into a situation where workflow notifications in Dynamics 365 Business Central were not being sent. To fix this, we had to do a few things:
1. Setup workflow users for notification settings. I will blog about this later.
2. Make sure the SMTP email server was configured to generate emails from the system.
3. Make sure each layer of workflow, where a notification needed to be sent, had approvals turned on to send to the original sender.
What became extra tricky was linking back in the emails to the original entries so when the users clicked on the link in the email, it would take them directly to the entry or card page. I had chose the page I felt was best, but then we were getting errors. I then found out with Microsoft that these links are page specific.
This blog post has to do with journal entry workflow. The page to link back to for journal entry workflow is page 39 as seen in the illustration above.
For each layer of your workflow where you want notifications to be sent, you must enable workflow notifications. If you want them to go back to the original sender, you must enable at every level. You can also have the notifications just go to a certain user as well.
Remember that if the BC workflow is too rigid, you can also utilize Power Automate/Flow to make the workflows whatever you want them to be. We recently had a client take all their Power Automate workflow approval entries and upload them to SharePoint so that they would have a full audit trail and que of items waiting to be approved and what was approved with comments for their audit.