> However in almost all normal cases, this grossly overestimates the required memory and thus leads to swapping when technically it is not needed.

This is not true. Disabling overcommit doesn't change reclaim and swapping behaviour and doesn't lead to unnecessary swapping.

> This is not true.

Yeah that wasn't correct. It will however cause the kernel to refuse memory allocations[1] which could have been allowed, and a lot of programs don't handle that gracefully.

[1]: https://www.kernel.org/doc/html/v6.13/mm/overcommit-accounti...