I may have started the thread a bit too early - it's not as exciting talking about new toys when they still haven't left mainland China...

BUT in other news, the forks arrived today - Rock Shox SID 110mm travel with remote lockout. $450AUD ($297.30USD).

Now all I need - and any help would be appreciated:

Drivetrain - 12 speed shimano preferred - any deals on Ali worth looking at? BB, Cranks, shifter, derailleur..

Seat post - Rigid to begin with, probably eventually move to a dropper post when she gets a bit taller.

Seat post clamp?

Saddle - something comfortable and light would be best!

FM-160PM adapter for the back brake

Stem and handlebar.

And I think that would be everything!

I used to have a similar power imbalance. You may need shims or insoles. However, just lowering the saddle 1.5cm for me made the balance equal.

After ride number 5 where the shifters stopped working, I have finally reached the point of permanently moving forward. Is there a way to use parts (such as the breaking calipers) in a shimano groupset?

I'm using LTwoo calipers on my other Ultegra mechanical road bike. They work pretty good and I was able to standardize my 3 bikes with the same brake pads (GRX, Ultegra and LTwoo).

I don't have any experience with eGR specifically but in general rear derailleurs should be able to pivot around that 'L-TWOO Drive Systems' screw, yes. In practical terms, this is useful when you want to remove your (rear) wheel but the cassette starts jamming against the derailleur; with a free pivot, you can push the derailleur back, allowing for a clear path for the wheel to drop down. This may not be an issue with your particular frame, however - I guess it's easy to test.

Thanks for your thoughts, that makes me feel a little better. I'm about to do a little maintenance at the end of the week in prep for a long ride I'm taking next weekend. I'll take one last look at it before I leave it alone for the time being.

It shouldn't break like that if it's a decent grade of well machined alu.  But it probably isn't, hence the result.  If you have an all alu cassette, then the smaller cogs are vulnerable.  But big cogs after very little riding is a sign of poor quality.

Yeah this is my take on it as well. SRAM’s alu cogs don’t break like this. And we have abundant 32 and 30t mtb chainrings that don’t break like this. I know that Alu inherently will wear fast, but it shouldn’t wear this fast.

I’ll also note that the treatment on the alu cogs was wearing incredibly fast.