What would you do?

Definitely Tube Preamp

I only recommend what I have owned, this Vintage McIntosh mx110z Tube Tuner/Preamp is the best one I ever owned. If something happened, I would get another one without considering anything else.

here's one, no wood case like mine. You can find them with wood cases, or find a wood case separately later, they pop up frequently.

This convinced me to get one, glad I did

https://positive-feedback.com/Issue77/vintage_mcintosh_experience.htm#:~:text=The%20MX110Z%20makes%20vinyl%20%26%20FM,modern%20preamplifier%20on%20Planet%20Earth.

After a year, I took it to audio classics, they replaced a few resistors, and the best improvement: they replaced all the rca jacks with new gold plated ones.

..........................................................

It is FULL Featured, has two MM Phono Inputs, tape loop ....

http://www.berners.ch/McIntosh/en/MX110.htm

I get remote volume/mute from my Integrated Amp.

Get a nice tube preamp. I like tube power amps, but also love gobs of power (even on those 96dB Tannoys), and it costs a LOT more to get there with tubes (like my VAC Master 300's). And after all these years, I have to admit Tannoys do great with either tube or SS power - they're truly ambidextrous. You might need to shut off the supertweeters for SS amps though - ouch! And the pre/power equation absolutely might flip if you're a low volume listener - I'm not 😅

Tube DAC - tubes are just an extra thing in the way, and I'd just let the DAC do its thing without a superfluous tube buffer. I suppose I'd have to hear a Lampizator to be properly qualified to an opinion here, but I've never invested enough in digital to go there.

I really love my current system and there is nothing lacking as E-650 offers a very sublime listening experience.

If this is true, then do nothing.

+1 tube preamp

Another option is to insert the Modwright Analog Bridge here