More changes would be needed than direct uniform scaling - .22lr is rimfire, whereas .45acp is centerfire, for example, and their aspect ratios are different. The mass and strength of uniformly scaled-down parts also might not match the recoil and pressure provided by the smaller round, and might result in failure to reliably cycle the action or the gun bursting if the mismatch is too much.
I have a 43-inch Insignia N10 that works great in exactly that role. Dumb TV with HDMI inputs, audio outputs, and that’s about it. Best Buy’s in-house brand, it was like 120 bucks about a year ago, when my Vizio TV from 2003 finally died in a way I couldn’t fix :(
The built-in speakers aren’t great, definitely recommend hooking it up to something else.