The cheap mylar stuff I call out everytime as a potential fire hazard, same goes for plastic. If you want to use a flex duct, make sure it’s a semi-ridgid aluminum duct.
There are approxametly 15,000 dryer fires a year.
Here’s another thread on the subject. Flue Metal vs Mylar Dryer Vent Pipe - Specific Inspection Topics / Interior Inspections - InterNACHI®️ Forum