To ask students to reflect without marking them, use a Long Answer block set to 0 marks. That is exactly what a legacy Reflection block becomes when a lesson is converted.
Setting one up
Click into the page where you want it, type /, and pick from the menu. Typing after the slash filters the list.
Choose Long Answer, write your prompt, and set the marks to 0.
What to use it for
A pre-lesson hook: what do you already think about this?
A mid-lesson confidence check: which part are you least sure of?
An exit ticket: what is still unclear?
Because it is not marked, students answer more honestly, and you get a read on the room without adding to your marking.