It’s gzip that caused your issue, not tar. The lack of index in tar is actually a strength for surviving corruption, as there are no critical areas, ie you can

It’s gzip that caused your issue, not tar. The lack of index in tar is actually a strength for surviving corruption, as there are no critical areas, ie you can lose any parts of a tar archive and recover useful data from the rest Tar.gz and tar.xz should never have been made a thing or become so popular, the only safe options are tar, tar.lz and to an extent tar.bz2