@sr20022002
"as long as its a sizeable upgrade from my RA-12"..."I’m a fan of a clean but less harsh highs, non shouty mids and tight controlled bass."... "Any help to reduce my anxiety or providing some suggestions would be much appreciated :)"
Do you need to buy/upgrade amps and speakers together all at once? Can you try a partial upgrade to start, to apply more $ to amp or speakers first.
+1 what spatialking said. "How" you listen is key for a SS vs. Tube decision. Also, might need to decide if you are stuck on McIntosh. Separates can be costly.
You could ask them to demo the MC152 before they fix the meters. Good dealers do demos. Try it with your LS50s and SB2000 before you buy. It will give you ideas, enough to decide to explore tubes or not.