Joining worktop no room underneath

Hi all. I'm fitting a kitchen, got a 3m x 3m worktop and in the corner there's a joint which we're doing with a router. However, due to issues I won't go into, the joining brackets will be right on top the corner of a carcass which we obviously can't cut out.

My dad wants to use one of those ugly metal joining strips but I don't like them.

My idea is to use the underneath joining brackets and do them up tight first, then lay the worktop.

Or, to use glue and dowells to join.

Any other...

Joining worktop no room underneath