The TMX/T150 is a entry level FFB wheel (2Nm)
The TX/T300 is a Mid level FFB wheel (4Nm)
The TS-XW/TS-PC/T-GT are high end FFB wheels (6Nm)
As far as I'm aware the only non DD (20Nm) base/wheel stronger than the TS-XW/TS-PC/T-GT base is the Fanatec Clubsport (8Nm). (I think the elite is (6Nm) on par with them but can't be to sure)
Give or take .1 or 2 here or there for the Nm, I just rounded them off.
So to answer your question, yes the TS-XW will be a big leap from your TMX.
Look here.
https://simracingsetup.com/product-guides/ultimate-sim-racing-wheel-comparison/
I'm also thinking about the TS-XW but only the base £350 as I already have pedals and wheel from my TX.
Failing that I might go straight for the Clubsport setup £700+