I got one about 3 wks ago but tried every well known big camera store all over the country and none had one available and then by off chance I tried a specialty camera store in Berkeley, CA that I've bought some equip from and they had 1 in stock (and 1 RF 1.4 TC) and I was able to get them both. Your best bet may be to try the non chain camera stores.
A friend of mine got his lens 7 days after ordering.
Perhaps a tip on this. I have been told that if Canon receives an order with a customer's name, it will process such an order faster. Of course, I can't prove whether that's true, but I ordered my R5 a week after it went on sale and received it 3 weeks later. Others who ordered well before me waited a long time for the R5. It was the same with the 100-500 lens. Ordered by the end customer by name, the lens was there after 7 days, others who ordered earlier are still waiting.