@catmint your trigger is correct but the follow on actions are not. First you MUST make sure that item versioning is switched on in your list settings. This is because we will be comparing the current version to the previous one.
So the trigger is:

Next, your first action should be "get changes for an item or a file (properties only)". You select the ID from the dynamic content box, then in the since field you need to add an expression to compare the current version with the previous one. That expression is:
sub(int(triggerOutputs()?['body/{VersionNumber}']),1)

Next, add a Condition to check if the Status column has changed, and if it has whether the status is now Completed (or whatever your statuses are):


It needs to select Status Value, not Status, because my column in the SharePoint list is a Choice column.
Finally, you update the item in the the list with the date the status was changed to completed, i.e. today:

Rob
Los Gallardos
If I've answered your question or solved your problem, please mark this question as answered. This helps others who have the same question find a solution quickly via the forum search. If you liked my response, please consider giving it a thumbs up. Thanks.