How do you handle using cutdowns in your Portfolio/Reel?

Hey, so I was wondering how other freelancers on here are handling to show off edits you did, that contain materials from other shoots/agencies and you are doing cutdowns or remixes for let's say TikTok?

There where also quite a few times where I worked for a couple of Porsche videos, where I got lots of material from other ads such as a Star Wars one and currently I do some videos for TikTok for McDonalds that are the behind the scenes/byproduct from an advertisement campaign. The campaign is from another big agency and I am employed by a different production company that is responsible for these 10 remix videos.

Would you say it's fair game to use whatever spots you edited, even if you only did cutdowns or did a whole other project and just reused those clips from bigger campaigns in your portfolio/demo reel?