New TV, problem

[Letterbox]

Hi, not sure if this correct forum ….had LG tv with sky q & Sonos surround, old tv packed in. Have since had brand new Samsung & Panasonic with same set up, many channels & apps no longer appear full screen anymore. Can’t think both replacements defective, am I missing a trick as to why new equipment has inferior viewing? Old LG was always full screen on all platforms. Is there a new TV. that would guarantee full screen in all broadcasts ? TIA