It's definitely a rabbit hole!
There's something addictive (to me at least) about finding something that was designed for a slightly different purpose and tweaking it to make it work better than the normal options for a related purpose. I wish I could get help for it!
This is the one that I would like to buy:
https://winstanleysbikes.co.uk/supernova-m99-mini-pro-25-e-bike-front-lightI really don't need it as I have a good solution already.
I have just dug out my RFR lights and thought about giving them another try, and remembered that lack of switch was one of the things that put me off. I could solder in a switch but it is extra hassle and creates an extra point of potential failure. I did get some inline USB switches (a bit of USB extension cable with a switch in the middle) but they were bulky, and really need to go inside a bag for waterproofness.
I've got the RFR 50 lux one on to see what time I get from a power bank, to compare against others. ISTR it didn't last as long as I'd hoped (other reason why I dropped it). I've got bigger power banks now than three years ago when I last looked at it so it might make sense to do it. Or I could just buy the Supernova... or get an 8.4V pack...