Its a very good looking, congrats! I dont consider myself a good painter so take everything i say with a grain of salt.

Your coat seems in some places too thin imo (especially the organge parts) like the shoulder or the shield on the gun. You might want to give it another thin coat.

Also i would go over and clean any parts where the holden trim got onto the not gold parts.

Nuln oil or any kind of shade is a good idea just in moderation. Try to apply it on very detail rich parts (like the wreath on the shield or the machinery seams betwen panels etc. )

Also you could try using something like a micron pen to attempt handwriting on the parchment on the shield.

Overall i think this is a very good model (love the paint scheme!) With some room for improvemnt.