RE komoot - I've used it a fair bit and think it's fair to say it's not meant to be a detailed route creation tool, more of a route share and ideas app. It's good for finding routes others have ridden and modifying them a little. But for creating a detailed route from scratch it's not as user-friendly as others plus it seems to struggle with UK ROW designations.
Can't comment on strava as I don't use it much, was interested to see if it came up much as an option though in case I was missing anything. I have a log-in to look at heat maps, mainly for MTB trails. Not sure I'd trust strava heatmaps for road riding, plenty of roadies use roads I'd go out of my way to avoid.
A local route. It's a good one but I know what you mean, it's also like riding on an MX track at times : ) (shout if you ever want some remote recce services in the Glos/Bristol area)The 2 bits of route I most remember are firstly, the Fosse Way.
TCR was always an interesting race format for this routing aspect. I'd wondered if there was an opportunity to race a good all-road bike and take route options that the guys on 28mm tyre TT/road set ups couldn't. I don't think so though - maybe here and there but not over that kind of distance.