My bias is towards good two-channel, so I like those suggestions the best. 😀
If it were me, keeping the speakers, I am auditioning the Audio by Van Alstine DVA digital preamp and DVA M225 monoblocks. And if I defer spending on better cables (hint: Iconoclast), I might have enough budget to snag a secondhand Lumin U1 Mini (streamer), maybe with the better sBooster LPS if I am lucky or patient.
There are a lot of interesting options to explore. This is one possible starting point that might be worth some homework. Good luck and have fun!