If you really want sound quality over all, then you definitely want a stereo integrated amp and 2 speakers. The performance gap is so great literally any integrated, the worst one you could find, will sound a lot better than the very best AVR you can find. No contest. You could even spend 2X on the AVR, still not match stereo. There’s good technical reasons for this I will be happy to go into if you want.
The Polks you have are $179 speakers. About the quality level you would expect if having to buy 4 speakers plus a sub. A much higher quality stereo speaker would be something like the Mini-Lore for $600
https://tektondesign.com/product/full-range-speakers/monitors-loudspeakers/mini-lore-monitor/#color Tremendous improvement.
The Mini-Lore is highly efficient, 95dB, so you won’t need a lot of power. This opens the door to incredible high quality in a low power amp like the Decware integrated amp
https://www.decware.com/newsite/SE34I.htmTake the time to read carefully. Do not be put off by the low power. The Mini-Lore with this amp will have your head spinning with sound quality you will not believe, all for $2200 speakers and amp. You mentioned 10 years. Decware offer a Lifetime Warranty! You will probably replace tubes a couple three times in 10 years.
You are willing to spend up to $5k. Split the remaining $2800 between speaker cables, power cord, interconnect, and some Townshend Pods, you will have an absolutely incredible system. Guaranteed beyond your wildest dreams. You will be hard pressed to find anyone with better that didn’t spend $25k. Or more.
This system will be highly expandable. The main thing missing is powerful bass. Which you probably don’t want in an apartment anyway. But down the road, add subs, boom now you have it all. Upgrade speakers some day, as long as you stay with high efficiency speakers like Tekton you are golden.
Big leap, nobody else here got the nerve to come up with this. Or the experience. They would, sadly, rather complain, or lead you down the well-trod primrose path. One thing you will notice, the stuff they recommend you can buy anywhere any minute 24/7/365. Tekton and Decware you will have to order and wait. That right there in itself is a clue who is recommending desirable quality and who has the same old same old. I waited 3 months for my Moabs, totally worth it. We got a guy here now 2 months into his Decware. There’s a reason we say these things are worth the wait: they totally are worth it!
