Erik, you seem to enjoy tinkering (as I have for some 40+ years building passive and active loudspeakers) and DEQX makes tools that are a tinkerer's dream. Go to their website and read up on them. Too many capabilities for a hunt and peck typist like me to explain on this thread. Feel free to DM me if any questions on the what's and how's.
Regarding the OPPO players, compared the 105 and the 205 balanced analog outputs into powered studio monitors----the 105 very good (I believe same dac as in your 103), the 205 (using newer processor) was an order of magnitude improvement over the 105 IMHO. The 205 also has six filter options (much fun) as well as MQA decoding (hope no one is triggered) if you like.
DEQX is coming out with newly designed products using newer processors and four channel capabilities (up from 3) to diy fully active speakers (8 channels). Can be used on conventional speakers as well, just not to the full benefit that fully active can provide (at the cost of more complexity).
BTW, I have no financial interest in DEQX or OPPO. Just feel as though I have some useful info/experience for a perceived kindred audio spirit.
This machine will also have you rethinking using a sub with your 2 ways.
Have fun!