Good evening sukhwinder and welcome to the Events Calendar forum!
Thank you for your interest in our products.
I would like to help you with this topic.
I have set Default venue for submitted events , but this doesn’t show as the selected. I am using custom user role to add events form admin dashboard.
Just to set expectations, as you might know, the scope of our support is mostly to get our customers started on the right track and to help them in case of issues.
We unfortunately do not provide complete support for customizations such as yours.
I would highly recommend getting our Community Events premium plugin: https://theeventscalendar.com/product/wordpress-community-events/
As an alternative, you could hire one of our recommended customizers to do the customization for you.
Best regards,
Geoff B.