We have a solid oak (some plywood) TV stand - well built and expensive when we bought it. It’s big downside these days is no large screen TV fits it. Over the years I have had to remove the doors etc to make a 40" TV fit, so our goal was to cut it down and have the TV sit on top. Also as the first picture shows the inside was just a dust magnet…
After the top was removed we measured twice and clamped a straight edge to the sides and I used a circular saw to cut sown the sides:
Finished - it will now take a 55" to 58" TV on top depending on the legs and we have a space to hide the sound-bar and electronics.