I have a requirement to send an escalation email based on the date difference between two date columns (considering business hours only). Is this accomplishable via SharePoint Designer Workflow or I should use Azure Web Job? which option is better to use?
SharePoint Designer workflows make it simple to set up processes that run when an item changes or is added to a list/library. If you want a process to run at a certain time, and then to run for all items in the list (or all items that meet some condition), then SPD workflows aren't the best option.
Webjobs certainly can do the latter, but we have another option as well: azure functions. Azure functions can run on a schedule, and can connect to a SharePoint list/library, and process items as needed.
Another option is Flow. This is similar to SharePoint designer, but is Microsoft's newer, cloud-based workflow tool.