I use the libre sensor as I like the convenience and the fact I can see my sugars levels for last 8 hours. I am a T1
Generally, sugars do rise before coming back down after meals but I agree that it’s best to have jab 10 mins before (unless sugars are already very low) One of the things I figured out with libre was that my background was actually too high and rapid ratio dose a little too low. This meant high readings after meals that dropped before next meals due to background still bring it down for next 4-5 hours. Since I corrected that, my control has been good and hypos are pretty rare, especially as I can test regularly.
Have to made sure your background is correct by having a zero carb day and seeing if your readings are constant. I just wonder if you might have same issue as I did.
Hope that helps.