But, based on what others have said about Wiim analogue outputs....it would seem likely that you could.
That kind of depends whether you've the Pro or ProPlus .... I recently got a Plus and plugged the analogue out into my amp so it's using the Plus's DAC and done back to backs with that against:
1/. Pro analogue out into amp using the Pros DAC
2/. Pro optical / coax out into a Topping E30 into amp
3/. Pro Optical out into my Arcam SA30 using it's onboard DAC.
There's a big difference between all of them except the last where I can't tell the difference, all the other scenarios are "thinner" and more distorted, the worst being using the Pros onboard DAC.
I don't think the OP can get any better quality than using a WiiM ProPlus, taking the music directly off the providers servers instead of to his phone, cable from phone to DAC .... you're just be introducing other things into the chain that may cause degredation ... unless the DAC he chooses has a "preferred flavour" than the Plus's DAC.