Digital Upgrade Recommendations

Looking to leverage the knowledge of the Audiogon experts for advice on how best to upgrade the performance of my digital front end to sound more like my vinyl rig.  Currently, I have a Roon Nucleus acting solely as a streamer feeding a Denafrips Pontus II via an Audioquest Diamond USB cable.  I’m looking to spend roughly $600 and the options as best as I can tell from scanning the forum are:

1. Upgrade the stock SMPS on the Nucleus to a good LPS power supply
2. Add an Etherregen and place it before or after the Nucleus
3. Purchase the Iris DDC from Denafrips and go I2S to the Pontus II
4. Other?

All suggestions and recommendations welcome!