As a start I will provide few thoughts for consideration that may help I and others provide helpful input.
From my perspective one problem you have is that the system you own seems very well balanced. Thus the 'where to start' thinking is understandable.
Have done anything to tune your room? If not would you consider doing so? Consider the room as a principle component of your system.
If looking to change the character of your system then a change in speakers would be a way to start. That may result in a change in amplification. If improving on the sound you have is the objective them improving the source components can bring about refinement. Thus you need to define your objective.
What is the priority between streaming and vinyl listening? As an example, streaming for me is background listening and a way to find new music. I otherwise listen to CDs via transport and DAC.
I would not put money into power conditioning. A surge protector by Brick Wall may be a good idea.