Wow, 9.3 really, really messed up my TCL 40S305 tv..
I was so excited to finally (hopefully) get the updated, because it's been advertised to speed things up a bit.
Nope, and quite the opposite. Some channels like Netflix and Amazon Prime take LONGER to access than before, and everything just seems the same as before, at best.
Another new "feature": My wireless connection to tv has dropped 3 times tonight, and I've had to reboot the TV each time to resolve it. It's 2 feet from my Google WiFi router, and before the 9.3 update, ran rock solid with that setup.
This is build 4175-08.
Honestly the speed this TV runs at is comparable to how my old Roku XS used to run at before I gave up on it and bought a Roku 3.
Thing is, I don't want to get rid of the tv itself- the picture is fine and the sound is adequate. The UI really needs to optimized and these bugs need to fixed.
Yeah, I got some Rokus. https://youtu.be/d1CSEeqWl10
I had v9.3 on my Roku 3 for all of 5 minutes before I "downgraded" (v9.2 is definitely an upgrade over 9.3). Saw all the problems you're seeing. This is why I go out of my way to block automatic updates on every electronic device I have.
On your remote, press Home 5 times, Fast Forward (>>) 3 times, Rewind (<<) twice. Do it all quickly and you should be in the "Secret Screen". Go down to "Update software" and see if it offers 9.2 as an "update". It may or may not and it may just update back to 9.3 when it gets the chance.