Since you have reproduced this on two Macs running macOS 27.1, with no third-party software installed, and confirmed that resizing works correctly on an older Mac running Monterey, I would suspect a possible TextEdit/macOS regression rather than a hardware problem.
I would first test with a new document. In TextEdit, choose Format > Make Rich Text, then select Format > Table to insert a simple table. Try dragging a row or column border to see whether the problem also occurs in a new document.
Apple’s TextEdit User Guide explains how to work with tables. When resizing, position the pointer over a cell border and drag when the pointer changes to a double-headed arrow. If dragging fails, check whether you can change the row and column settings through Format > Table. If the menu controls work but dragging does not, that would be useful evidence that the problem is specific to the dragging operation.
If you have not already done so, you could also try starting your Mac in Safe Mode to help rule out certain software-related causes. However, given that you’ve already reproduced the problem on two Macs without third-party software, I wouldn’t spend too much time pursuing this possibility.
I’d also check System Settings > General > Software Update to see whether a newer macOS version is available. I wouldn’t recommend reinstalling macOS or erasing either Mac at this stage.
If the problem persists, I’d report it to Apple through its macOS feedback page. Include your MacBook Pro model (M1, 2020), the exact macOS version and build, the steps needed to reproduce the issue, and the fact that resizing works correctly on Monterey but fails on two newer installations. A short screen recording showing the unsuccessful drag would also be helpful.
I haven’t found an Apple-published fix specifically addressing this issue, so it would be premature to say that a confirmed bug has been identified. Nevertheless, your comparison across three Macs and two macOS generations provides a good basis for reporting a possible regression to Apple.
One detail that might help narrow down the cause: when you position the pointer over a table border, does it change to a double-headed arrow but dragging has no effect, or does the pointer never change at all?