I have been having same problems with my wifi disconnecting but no issues with other devices on same wifi. We just wired it directly to a router but reading all of your issues I do not think it will solve the problem.
I also have issues with my tv sound, we have to run the sound test everytime we turn on TV to get sound. Please fix!!!!
model- 75UJ6470-UC
WebOS TV version 3.8.0-61208