I noticed how the cover was attached when I first got my 2019 Redline. I replaced the plastic fasteners with truss headed stainless steel screws, flat washers and Nylock nuts.I saw your post and I have the same problem with my 2020 Equinox. When you spend this kind of money, we shouldn't have to have a cheap piece of plastic hanging . I bought my certified 2020 Equinox last summer and noticed that the cover was not attached securely across the top. I mentioned it to the sales mgr and he said he had alot of covers on hand and said he would replace it. This cover stayed in place for about a year and now it lets loose across the top. The attachment tabs on the bottom have kept it from dropping off. But it looks awful cheap when GM expects us to pay 30 to 40K for a vehicle. I'm gonna push the issue on my next oil change and see if there is a fix for this hitch cover.
This assures it is secure as it requires tools to remove now.