Is there anything wrong with my planned itinerary for RTW Qantas oneworld redemption?

Hi everyone - another post about RTW trip planning and hoping to get some guidance if this is feasible?

I’m based in Sydney and trying to put together a plan similar to this article (Perks of starting your Qantas oneworld Classic Reward overseas) by positioning my starting flight out of BKK.

BKK-HEL-BER (Stop 1 in Berlin)
BER-LHR-ATH (Stop 2 in Athens)
ATH-CDG (Stop 3 in Paris)
CDG-LHR-SIN-SYD (Stop 4 in Sydney with a long transit back home)

And then resuming months later

SYD-SIN (Stop 5 in Singapore)
SIN-SYD (Return back home)

Would obviously find a positioning flight to BKK to start - but wasn’t sure if the SIN/SYD legs would work?

Any advice or guidance much appreciated!

The itinerary seems to check out fine to me. After revisiting the rules on some of the PointHacks RTW articles.

Disclaimer: I’ve not done a RTW redemption before.