@Ton-Machielsen I guess you mean this one:
https://www.myrouteapp.com/route/open/10719669
OK, a few thoughts/suggestions:
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point 1 is not on a road, so there's quite a high chance that you didn't pass through it as you set off. An easy fix is to just shift it a little way ahead of where you start from, and put it directly on that road
Like so:

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most of your waypoints aren't on a road - they're just kind of close. Use the magnifying glass to zoom in and get them on the road. (The magnifying glass is in the pop-up that is shown when you click on a waypoint.) Waypoint 7, for example, is right between two roads:

I'm guessing the road to the left is the 'correct' road, but you will have got taken along the right one, and then back again, I think. Quite frustrating!
The same for waypoints 6, 11, 12, 16.
Lastly, the end waypoint isn't on a road either. I'd put it say 100 metres before your destination, just so you're guaranteed to pass through it.
I've made a corrected route for comparison:
https://www.myrouteapp.com/en/social/route/10725113?mode=share
Lastly, another reason to be very accurate with waypoint placement is on dual carriageways - I'm sure you can imagine the pain caused by selecting the wrong side of the carriageway!
I'm sure there are other improvements, but those came to mind immediately.
I hope that helps you a little.