I know a guy that works in shipping for a vendor. He told me that in March, they could sent out as many packages as they wanted (FedEx). By May 1, they were told by FedEx they could only pick up 60 items a day. By June 1 that had dropped to 40 a day. They switched to the big brown trucks, they are being throttled now, too. The only carrier that I get stuff from reliably is USPS. I've stopped ordering from vendors that ship FedEx, not because of the delays I've mentioned, but because they are - in my case - so unreliable it is infuriating. I had a package that was in "delivery exception - address doesn't exist or cannot be found" for 7 consecutive delivery days, yet in that same period I got 3 other deliveries from FedEx as scheduled. When it did arrive, it was delivered in a Ryder truck that was filthy and had a broken windshield. I've had consistent issues with them for the last 7 years, at least 50% of my items show up 3 or more days late, partly due to their shipping software. We share a ZIP code with 5 other towns, even if I do a +FOUR ZIP, they list it as the wrong town. Some vendors allow me to change it, if they don't, I won't order. The town that is the "main" ZIP is on a different delivery route than my little town, I've seen the driver's delivery sheet for the day, it has the wrong town on it, if they don't look at the actual label, it won't get delivered, and it is never the same driver week-to-week. I have zero confidence in them. UPS is pretty good, partially because the guy on the route has been the same since I moved here 7 years ago. He comes in the same 30 minute window every day, and even those Surepost deliveries that are supposed to go to USPS to be delivered, he will skip the middleman and bring to me.
TL: DR - things are tough all over, if you need it ASAP, good luck with that.