If you are willing to TRY a class D amplifer, VTV makes a few different models class D amps, some with tube input buffers, others with different Op-amp choices to flavor the sound in the direction you want to go. These all have a 45 day trial period available which should be enough time to do a fair evaluation of the sound quality. Modules used include Hypex, Purifi, to name a couple and are available at different power levels, there are enough choices in power level you should be able to find something that works for you. I just recently got a 500 wpc Hypex based amp from them for roughly 760 bucks and I love it. Cool running, very clean sound quality, hard not to like efficient, good build quality and affordable with good sound. Class D is the future of amplification and it has arrived...its way better than anything I have heard regardless of price.
https://vtvamplifier.com/