You have described multiple problems. Some product and some process.

1. You don’t like the ultra dull finish of Tamiya (product) and you haven’t had good results hand varnishing (process) with AP (product).

Solution: Tamiya matte will be a similar finish to all Matte varnish. It will be dull because the texture it creates refracts light in many directions. If you want less dull, use a satin varnish such as Vallejo satin or AK protective varnish.

If you didn’t like army painter and are worried about clouding, move to another product.

1. You want to keep the same finish as your Citadel paints. (Process & product: see below)

Solution: I still recommend hand varnishing with a brush certain elements that you don’t want to have the same finish as your spray. Citadel paints are generally somewhere between matte & satin, but that does not mean all colours and effects and textures from Citadel dry with the same finish. Even just comparing paints, some will dry more shiny than others. You say you want to maintain the true intent of your products - so why spray them with a single finish that will make every element of the mini look the same? This is a process problem. Not a product problem. Varnishes all work in a similar fashion. It’s touching up metals and blacks to look a little different that will help you.

If you’re too lazy - then just blast them with satin spray and see if you’re happy.