Oh. Well in that case I do hope its Hillsdale.
Also good to know your plans. I tend to think long term when it comes to my system. This was 2004
https://www.theanalogdept.com/c_miller.htm and this is 2020
https://systems.audiogon.com/systems/8367 A lot of the same stuff even over 15 years. A lot of new too. Pictures aren't sound but be assured huge massive improvement in sound. Slow and steady. Smart well thought out choices that last a long time beats frequent flipping.
Anything you get will be head and shoulders better than your Yamaha AVR. The question is more are you looking for an anchor piece like you said or was that more colorful language? It really helps to know.
Because a used amp like my Melody for example would be in your budget. And don't worry about tubes, with adult use tubes last many years. A typical amp like mine uses KT88, a set of which is under $200, and lasts a few years. Most guys change tubes because they want to not because they have to. The sound quality you get from tubes is unmatched with SS.
Any used tube integrated in your price range you will not believe how much better it will be than what you have now. Any. But if you really want an anchor there are some truly impressive integrateds in the $3-5k range that could be considered lifetime components. Or if not lifetime then long time like my speakers and turntable, or the phono stage in 2004, all in the 15-20 year range and all of which were at one time "anchor" type components for me.
Another thing about long term, it helps to think of the whole system. If you're using hook up wire, patch cords, and freebie rubber power cords those are low hanging fruit ripe for upgrade. Something like a Creek that leaves room for better speaker cables might make more sense.
What wire are you running now?