Reinstall latest kernel without having useful kernels

While trying to make disk space on my vintage VAIO to make space for Debian 4.19.0-14, I mistakenly arrived at vmlinuz-4.19.0-14-amd64 and previous 4.19.0-13 being truncated (premature end). Loading initial ramdisk ..... you need to load the kernel first. But I have no more any useful kernel to switch to.

As I have a lot of finely tuned software installed on both /usr and /opt, how to repair? I have KNOPPIX 8.6.1 or the 2021 live ARCH CD, perhaps easier (howto?)

thanks for advice about this non new issue
francesco pietra