EDMX is very cumbersome to use after certain DB complexity. We are at a point where we want to get rid of it but still we want to update DB first and get the model changes. Is it possible?
Yes, as long as your code-first model matches your database. It will map correctly without a need for an EDMX, but this will mean you have to manually update your models or regenerate your code-first files.
More info can be found here: https://docs.microsoft.com/en-us/ef/ef6/modeling/code-first/workflows/existing-database
Another option is to use entity framework migrations. Instead of letting EF apply the migration, use Update-Database -Script
and this will generate a sql script to apply it manually. This wouldn't be db first, but you could make changes to the script before applying.