Bought a new TV in the last blackfriday and only when unboxing it I realized the TV wall mount I had was limited to vesa 100 while the new TV required vesa 200.

It was late in the night so I made this quick-and-dirty adapter in Tinkercad.
https://www.tinkercad.com/things/0IjoP84wlQE-vesa-adapter-100-200

I admit it's not beautiful but I can ensure it is strong!
The vesa 100 holes are 4mm and the vesa 200 holes are 6mm.

Printed with 1.5mm walls, infill 22% and 2mm layers. No need for support.

You'd need a big printer bed I'd say 250/260mm.
That wasn't a problem for my HyperCube Evo 300. :)

It fits perfectly in my new TV.

Although my new TV is bigger than my old one, it is actually lighter, so in my case this adapter is perfect. Your mileage may vary so use at your own risk and if you need to change any part of the design there is a link in tinkercad for it.

I recommend the use of washers (those small metal doughnuts for the non-native speakers) in all screws just to make it safer.