Hi, I have a Spatial X5 and I am using a Balanced Audio Technology (BAT) VK 3500 integrated amp with Russian military super tubes for the internal preamp and a solid state amplifier. I’ve always thought this is the best of both worlds. It also comes with a high-quality phono stage. Originally this was to be an option, but they ended up making it standard. https://balancedaudio.net/vk3500-integrated-amplifier
These originally cost $12,000. I see several on HIFI Shark in the $5,000 range.
Here are some reviews.
https://www.hifinews.com/content/bat-vk-3500-integrated-amplifier
https://pt.audio/2021/09/26/balanced-audio-technology-vk-3500-integrated-amplifier-review/
https://audiofi.net/2021/06/bat-vk3500se-a-modern-sonic-masterpiece/