Would an external clock “help” in this signal chain?

My system sounds quite good to my ear. But I did spend a lot of time battling a harsh top end which I seem to be especially sensitive to. It’s now pretty great but I can’t help but wonder ‘what if??’ when I think back to all these components I’ve added and how each added to the overall character. 
 

Specifically I’m considering an external clock (or two?) in this chain. Also curious about using a grounding block. Maybe something else?

Here’s the signal chain:

iFi LAN iPurifier (converts signal to fiber optic and back)

RJ45 Cat8

Uptone EtherREGEN

RJ45 Cat8

WiiM Ultra (is this a bottleneck? Thought about Holo Red)

USB 

Singxer SU6

I2S

Gustard R26

XLR 

Tube Pre

XLR

Buckeye Hypex NCx500

Wharfedale Linton 85th

Everything is run through a Synergistic Research Power Cell (scored it used and it still broke the bank).

Either iFi Elite or chinesium linear power supplies. 
Power cords are Viborg. 
Interconnects AudioQuest Cinnamon. 
 

Thank you!