Yeah, I'm afraid with the shortages/delays on so many things it will be hard to pin it on the dealer. I wonder if they have any vehicles just like yours on the lot? If you made a big enough stink, maybe they would pull the part from a yet to be sold vehicle and let that one sit in order to avoid the bad PR.*
The covid makes it really hard to know what is going on in a lot of industries. In some cases, the parts actually are floating around on the ocean, unable to be delivered. In other cases, people use the covid as an excuse. I had lunch with my realtor friend around a month ago, and she said title companies and loan companies continually use covid as an excuse for delays, even though it doesn't seem to make sense for covid to affect a title search.
*Google reviews can make a difference. I got hosed on something when I bought my F150 back in 2016. Dealer made promises regarding missing items in the truck that the salesmen kept blowing off after they got their check for the truck. I finally got sick of it and wrote a detailed one star review on Google. I got a call from the general manager the next morning and got it resolved within 24 hours.
If you write a negative review, avoid making it emotional. Detail the problem using neutral, non-whiny language. Because if you go on a rant, it just looks to readers like someone who complains about everything, and the dealer might ignore it.