The only decent, modern Sony 4K TVs for demanding users running Android TV are the ones that have the newer snappy MediaTek (MT5893/5895) chipsets under the hood and now have the ability to be able to upgrade to Android TV v9.0 Pie.

Every other Sony TV model by comparison used dinosaur old, slow underpowered chipset for running Android TV. They are frankly obsolete as a snappy Smart TV in comparison to modern tech. Use them as a display only.

The solution for those owners is either buy a Nvidia Shield or now get a new Google Android TV dongle.

Previous iterations of Android TV were laggy depending on the hardware, however, starting with Android 9, Google made an effort to improve the OS with low end hardware or with low memory RAM, I imagine yours is still on Android 8 or less.

1. Have you checked the Sony website for your model to verify if there is any software update available?, Sony has been releasing software updates in recent months but they are mostly in the support websites.
2. The device will be officially announced on the 30th so it's just a matter of time for it to arrive worldwide.

I have a 2016 Sony and keep it up to date via the Sony website as has been mentioned. It used to be laggy in the early days but not any more, doesn't bother me at all now.

I have a x900e and it was pretty laggy. Make sure it's on the latest software and then go to app settings and disable most of the crap that you can't already delete. It helps a lot.

Make sure you have the latest firmware update for your tv (check on sony's support website), factory reset your tv and when it reboots make sure you do not enable samba tv , you have to select no twice. Disable all apps you don't use.