Best Bang for the Buck Upgrade

Given the speaker quality and you like them. Probably the DAC… it will improve the transport sound quality and set you up when you do go to streaming… today streaming can equal or exceed the SQ of a transport.

Long term improving systems are typically done by choosing the first component that will give you a big boost… and upgrade it to the next level… then bring up the other components. So first DAC, then integrated amp ~$10K new… Streamer ~$5K… then your system would be at a whole new level, taking advantage of your speakers.  Assuming each choice carefully made.

Is is a tough one. You have a very nice system already. I hate to say it but since everything is well sorted you have no choice but to change loudspeakers to get to the next level. It's going to stretch your budget to get to the next step.

@hilde45 beat me to it. It really depends on what sonic improvements you’re looking for. I think you’ve got some really good speakers, and the fact that you seem to connect well with them, well, that speaks volumes to me because that ain’t always the case. Not familiar with your amp, but if I’m you and with your budget, I’d get a Denafrips Pontus ll DAC and and Innuos Zen Mk3 streamer/server and a Qobuz subscription. Load all your CDs into the Zen and enjoy not only all your music from your chair but get exposure to worlds of music you’d never have otherwise heard. Seriously, being able to access an unlimited library of music, much of it in hi res, has brought me more enjoyment than any equipment upgrade I’ve ever made. My math says doing this will still leave you with around $5k left over, and with that I’d add a couple good subs, which will take you to a MUCH higher level not only in bass but in imaging and significant expansion of soundstage.  Just my $0.02 FWIW.

Would you consider spending $500 on a Black Ice Audio

Foz SS-X Sound Stage Expander?

Nice system!  Assuming your room is not an acoustic disaster in need of major treatments, I would look at replacing your transport/DAC with something like the Luxman D-03x CD player.  You also might consider a power conditioner.