Looking at your list, I would start in this order; good luck!
1. Power Source conditioning &/or dedicated circuit
2. Room Treatment: Room selection/ Audio furniture (vinyl playback)/ Equipment placement /absorbers/diffusers
3. Cables with existing components (my preference is to start with Power Cables then Speaker or Interconnect)
4. Component power supply (address those first with wall wart power supply).
5. Component upgrade
Point #3, it’s unlikely that you find any consensus as everyone who believes cable matters have their own methodology. Just ignore the cable naysayers:-)