If we abolish leap seconds (and any other changes to UTC) and let the error accumulate until it hits 30 minutes then a 1-hour time zone change can adjust for it. Time zone changes happen at least semi-regularly so it wouldn't be monumental.

It would take millennia for such an error to accumulate. Leap seconds are inserted less than once a year and 30 minutes is 1800 seconds.

Falsehoods programmers believe about leap seconds: 1. The rate at which leap seconds are inserted will remain roughly constant. [...]

The Earth's rotation is slowing down (by about 2 ms per day per century), so the difference between TAI and UT1 is increasing quadratically, not linearly.

Wouldn’t that move the international date line?

I guess so, but I don't know why that matters.

The international date line isn't straight in order to avoid land. Moving it would be problematic.

think of it as ordinal: you're shifting left 1 unit, not moving the line, per se.

Still matters because some places want to make sure it's the same day (according to their local reckoning) as it is somewhere else in particular (usually a major trading partner).

Or the next town over.

The other boundaries are a lot straighter.

Imagine what would happen when the International Date Line ends up in the middle of the US.