Maybe try 5.3.0.24.28?
$ rmadison linux-generic linux-generic | 5.3.0.24.28 | eoan-proposed | amd64, arm64, armhf, ppc64el, s390x linux-generic | 5.3.0.24.28 | focal-proposed | amd64, arm64, armhf, ppc64el, s390x
Maybe try 5.3.0.24.28?
$ rmadison linux-generic
linux-generic | 5.3.0.24.28 | eoan-proposed | amd64, arm64, armhf, ppc64el, s390x
linux-generic | 5.3.0.24.28 | focal-proposed | amd64, arm64, armhf, ppc64el, s390x