Hi @Sufy B_
It's Violetta from Planyway:)
I'm afraid Trello calendar doesn't allow you to visualize custom fields, only start/due dates.
As an alternative, you may add Planyway power-up. Planyway can show date type custom fields on the timeline or calendar. Using filters, you can easily spot them. Here’s a simple instruction on how to do it:
Additionally, you can add custom filters based on checkbox or dropdown types.