Please refer to the following comment from the development team.
LSDK yocto tiny RFS doesn’t contain openssl package to keep it tiny by default.
Users can generate LSDK yocto devel RFS which contains openssl and more packages.
e.g.
$ flex-builder -i mkrfs -r yocto:devel -a arm64
$ sudo find build/rfs/rootfs_lsdk2004_yocto_devel_arm64/target/ -name openssl
build/rfs/rootfs_lsdk2004_yocto_devel_arm64/target/usr/local/bin/openssl
build/rfs/rootfs_lsdk2004_yocto_devel_arm64/target/usr/local/include/openssl
build/rfs/rootfs_lsdk2004_yocto_devel_arm64/target/usr/local/share/doc/openssl
build/rfs/rootfs_lsdk2004_yocto_devel_arm64/target/usr/bin/openssl
build/rfs/rootfs_lsdk2004_yocto_devel_arm64/target/usr/include/openssl