It's easy to set certain events as movable or unmovable permanently in your settings under Conflict Resolution!
Enter your Settings through the upper right-hand drop-down menu.
On the new screen, select "Conflict Resolution" on the left-hand side.
Add keywords such as "lunch" or "break" to mark conflicts that have the noted keywords as "movable" by default.
Similarly, add additional keywords to mark conflicts that have the noted keywords (ex. OOO or 1:1) as "unmovable" by default.
Again, these will automatically set events as movable/unmovable when building loops and sorting out any conflicts on the "Results" step.
Don't forget to click save before exiting!
Note: These are company-wide settings