audio output

I have just reappeared from the never-ending internet rabbit hole of all things audio output. Perhaps someone out there can help me resolve a seemingly impossible conundrum?

I own a mac mini 2012 version - both memory (to 16mg) and hard drive (to SSD) have been upgraded.

Having recently subscribed to a HiFi streaming service and downloaded a fair amount of quality lossless files, I would love to use the mac mini to playback over my amp/speaker system.

At the moment I am having to stream from the mac to my Onkyo amp (which boasts a superior Wolfson DAC) via a cheap Bluetooth receiver (actually, it's an Esinkin - please don't judge me!).

At the risk of opening a pandora's box of all things audiophilia, I am really looking for a simple solution here: for example, should I ditch the Esinkin and buy a stand-out receiver or look at buying, instead, an audio adaptor interface? I don't want to go down the well-established route of using the headphone output.

I am using Vox to playback the hifi files - files are FLAC at around 700kbs, 16 bit at 44.1khz (which I believe is the maximum for this mini). I understand that with a measure of good advice, good luck, and a few $$s I can increase the output to 24 bits at 192khz. Such dizzying heights and I'm sure I will notice almost nothing! Still, it's all in the fun of the chase!

Thanks in advance for being polite and kind..!!