Trying to get a general idea of SQ hierarchy for combo pre/DAC vs separate boxes

How does a combo preamp and DAC compare to separates? And do you spend more on the preamp or the DAC? I started out looking for comparisons of the PS Audio Stellar GDC because I liked the idea of its analogue volume control, but there are a lot of options. With separates I might upgrade my DAC first before I start messing with anything else. Here's a quick list with current prices on both sides of the GCD:

$ 900 - Schiit Saga ($300) & Bimby ($600)
$1500 - Schiit Freya+ ($900) & Bimby
$1550 - Schiit Saga & Gumby ($1250)
$1700 - PS Audio Stellar GCD
$2000 - Benchmark DAC3 L
$2150 - Schiit Freya+ & Gumby
$2200 - Mytek Brooklyn DAC+

Current system is Dynaudio Audience 82, Musical Fidelity A300 Integrated, Oppo BDP-105 for discs and DAC. Leaning toward a PrimaLuna power amp, either HP stereo or monoblocks . The list of speakers I want to listen only gets longer the more I read so I'm putting that off for a bit. Might try streaming and a dedicated server eventually. Most of my CDs are already ripped lossless on an SSD plugged into the Oppo, but the interface is heinous. Ripped files through the Oppo sound fine, but I really miss the AH! Njoe Tjoeb I had until the transport finally died. I think that may be what is making me want to go the tube amp route.