Low hanging fruit is very low hanging in this case. There are many point mutations for example that confer risk to disease and cancer. Lynch syndrome which confers significant risk for colorectal cancer for example is something that could he cured with transgenic humans today even with todays technology. Just a matter of screening gametes for the mutation (usually one base in the case of Lynch in heterozygous state with wild type healthy allele and that wild type healthy allele gets a second hit mutation as the cancer develops and things just go off the rails from there) and editing that base back to wildtype. No downside only upside with that.

What gets harder are polygenic traits that even today we don’t have great data on what are the causal alleles. But that is also not a technological limitation either but a statistical one from insufficient sampling of these polygenic phenotypes.