I had a planet x sl quite a long time ago and I like it, it was pretty light and rode pretty well. Nice and comfy compared to other carbon frames and alloy frames Ive used.
Probably can’t go wrong with a Giant or a Cannondale though.
As for fit, it’ll no doubt change over time, just buy some cheap stems in different lengths so you can play about. Think Ive got over 200 quids worth of stems kicking about just from chopping and changing my fit and bike. Started with a 110 on the PX, the stem on my current bike is 140, had various sizes in between