I don’t think a separate amp,is the best route.
My experience has been a quality preamp accentuates the source. I used to use an integrated amp. I added a preamp (MC 2600) and it impacted my system so much I have replaced the integrated amp with an amp, upgrade the DAC, turntable, speakers and interconnects in order and with significant impact.
The last upgrades were Sonus Sonetto Vs to Sonus faber olympica nova Vs and Kimber Kable loom.
My experience has been a quality preamp accentuates the source. I used to use an integrated amp. I added a preamp (MC 2600) and it impacted my system so much I have replaced the integrated amp with an amp, upgrade the DAC, turntable, speakers and interconnects in order and with significant impact.
The last upgrades were Sonus Sonetto Vs to Sonus faber olympica nova Vs and Kimber Kable loom.