I would go with the SK6812 5 meter strip 30 count per meter. Without actually measuring think the 5 meter would make it around your TV. Also at the 150 led count you probably would not need another power supply. And if you do the 60 count I think that would exceed DS capability anyhow. There is a german company that makes a 45 count per meter but pricey to acquire it.
DS Flex strip count (IRC) is 24 LED's per meter. So the 30 count would be a step up anyhow.
I had got mine from Amazon but they are not available from that seller anymore. I had also seen them on ebay. As for the 42 count I can not remember but found them through a little googling...but as mention was a german company and the cost was up there. However WS2812B are also a good choice of LED and are more plentiful. If I may suggest that for the TV mount you check Amazon as that one from bestbuy is pricey and you could get a nicer more flexible one for half that.