I would give some thought to how you listen. Do you enjoy the hidden details in recordings? Do you want a flow of music you can immerse yourself in and relax?
I think most who try a neutral amplifier find it harder to engage especially if coming from tubes.
Excellent SS amplifiers are...
I find it hard to believe a spectral amp would oscillate if using a spectral preamp and competent cables. Their preamps monitor this and would shut down if it was upstream or in the preamp. A well shielded cable, especially balanced xlr should be totally safe to connect the preamp and amp.
I would try the benchmark audio digital xlr. Canare digital design. Moderately priced for a 6’ cable.
https://benchmarkmedia.com/collections/cables/products/benchmark-digital-xlr-cable?variant=547880281
Ron have you read Scott Frankland's comments about EL34 tube and designing an amplifier to take advantage of the EL34 properties?
https://positive-feedback.com/Issue14/franklandinterview.htm
Its a nice read and keeps me interested in EL34 based amplifiers and tube amplification in general...
I am eligible for several one steps. I decided to let it be. I have 2 unopened Abraxas, they might be worth more on eBay. Nightfly is a digital lp. I think have three more from the earlier one step releases.