First, you can hold down the ctrl key to select all the blocks of your flowchart, and then right click, and a' combination' option will appear. You can click on the combination and let them be combined according to the current layout, so it is not easy to be confused.
In fact, whether you are writing a paper or editing other documents, I suggest that you use viso, which is specially used for flowchart design in office, to design flowcharts. You can design your flow chart in viso, and at the same time, you can modify the design text, font and alignment in it, and then copy and paste it into word, which will automatically become a combination and can be scaled freely. If you feel bad, you can redesign it in viso, which is very convenient.