First off all, if you get a light with a proper cut-off, 500 well placed lumens are more than enough. I'd recommend the B&M IQ-XE, it's an e-bike light that accepts inputvoltage from 6-48V, so you can attach a range of battery packs there.

If the sky is the limit (moneywise...) , you might look at lupine, the have a nice set of the SL-AF with an proper adapter for canyon aero bars, and you'll have plenty of light...

If you want spent less, you might look at adapters from raceware.co.uk (as you already discovered), also take a look at hidemybell (https://www.closethegap.cc/product/c...h36-h11-ready/), the also sell just the part that attaches to the stem/bar as spare for 10 Eur, and it has an GoPro mount. Outbound Lighting offers also a outfront GoPro mount, and their Road Edition is quite a bit cheaper than Lupine (and still does pretty well, i have both...)