Elena999 said: Does it make any sense to buy this device or something similar to measure sunlight time?
https://www.amazon.com/dp/B07Q56D14Z/
Don't make this more complicated than necessary. You need a clock, pencil and paper.
Starting early in the morning, write down on the paper as soon as you see sun on the garden bed. Than keep checking the area every hour adding notations.
For example: sun 7am - 12 noon, shade 12 -2, sun 2 - 5 Total sun 8 hrs.
When you do the map, you could divide your garden bed in half. (the sunnyside where the veggies were planted and the other side).
You could plant some of your roses in the ground where you have most of the sun. And the remaining roses in containers like Porkpal suggested. They can be moved around using a planter tray with wheels.
And if necessary, you could add a couple of outdoor grow lights as Rose_Guy1127 did.
Here's a photo of a map I did of my garden beds. It will be difficult to read but, I think you will get the general idea.