“In the day”, I would buy a separate pre-amp, power amp, tuner. This provided a single item upgrade solution.
(For awhile that was also my approach to home theater as well. Now I use a Denon with three outboard Onkyo power amps).
For my stereo, I use an integrated amp (separate pre-amp did not seem to provide additional flexibility), no longer use a tuner (have one but it is boxed and set aside). ROCK, DAC, Streamer are all separate units. I could trade-upgrade any components if desired.
If one had space restrictions (and/or budgetary) a single component solution would have a great deal of merit.