My experience has been totally the opposite of the OP concerns, and my car did not have all of the updates when I purchased it (it does have everything other than H264 now, including the 19C SOTA update). I will admit, that given some of the issues that have been widely reported in various forums and Facebook groups I keep expecting some major failure to hit my car, but so far so good.
As noted, the car is heavily software controlled, and just as with an older version of an OS on your personal computer that is not patched to the latest versions things can be wonky, it is hyper critical to get the car verified as to what needs to be updated, and have those updates done ASAP. You can check what update campaigns are due for your car needs by going to the Jaguar Topix web site, located at https://topix.jaguar.jlrext.com/
. Once there you will need to register on the site, you want to setup your account using the lower left black button labeled "Independent Operator". Make sure you have your VIN handy. Once you create your account and setup yourself as an Independent Operator, and have logged in, on the next screen enter your VIN. The website will take a few moments to look up your VIN and will return the current campaign/s outstanding for your car. Print the page with any campaigns for your car and take it with you to the dealer to prove that your car needs the specified updates. Some dealers will have it all in hand and have the updates needed already on the work order, some may need the page you printed out.
And as noted above, have your dealer use their Pathfinder system to diagnose the car.
If after all software updates have been applied you still have the plethora of bad issues with the car, since you are in the USA execute your rights under the lemon law.
And by the way, I purchased my car from the Bellevue dealer, they have been accommodating, and had all of the updates I had on my Topix report already on my work order when I took the car in before the holidays.