I continue to enjoy my Theta ProBasic IIIThis is already a good dac..... i think that perhaps you would better do to invest more time, and less money in the controls of your room acoustic, and in the cleaning of the electrical noise floor of your house and perhaps even in the controls of vibrations from the speakers...
But audiophile experience is for me synonymus with a controlled acoustic, not with the choice of a dac mainly....
It is only my very limited experience but very convincing one for me....
My actual dac sound limited in my non controlled room and is not the same at all in my new controlled room.... The dac has not changed a bit, my evaluation of it has.....Upgrading it then seems pointless now for me ....
Sound in an abstract way is equally wave or bits, but in a concrete room sound is mostly only specific space and waves for specific ears, not bits....
And at the end you will be better prepared to upgrade if necessary after an acoustical optimal installation...Or even after an electrical grid controls, etc