I wanted to follow up on this - I did upgrade from a 3700X to the 5700X3D and what a difference it's made! Thanks for the good advice.
Whilst gaming has seen the best improvements - the stuttering and frame drops even at modest settings (with a 2060 Super) has been eradicated (and I now even have a touch extra headroom to improve some settings since I was previously CPU bottlenecked), I've also noted performace improvements in Lightroom since it does utilise the GPU, I suspect that fatter cache may be helping somewhat, but it's less notable than game improvements.
Thanks again.
Now, about those GPU prices....