I'd love a kicad plugin where not just lead times but current stock etc are showed live, and for anything marginal a button I can smash to order it in advance.

Even if 50% of the time I didn't end up using that component, that would still be an amazing service.

We pre-order parts to JLC during the design process. I know people using JLC aren't your target but my advise would be to not ignore how gloriously friction-less it is now buying parts into private inventory - and with no ongoing fees as well. They have really nailed it.