Help more source a rattle please!

[brisk00]

2019 LT Trail Boss 45k miles. I'm getting a consistent rattle from the passenger floor board area. It only happens upwards of 65-70 mph. I've removed the blower motor and drove around and it was still there. It has a plastic sound and is not constant. It happens every few seconds or so.  Unfortunately I haven't been able to get a clear audio recording of it.  Please help! It's driving me mad!

 

Edit:  Found it!  My fender liner was missing a couple of screws.  It was flopping around the wheel well at high speeds!

Edited April 3 by brisk00

[19 Denali ultimate]

I'd check the rubber covers where the hood hinges come up through when the hood opens near the base of the windshield.  My passenger side one was loose and not locked/snapped in to place properly.  Although I found this by accident, i was not getting any noticeable noises.