These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.09 s (backtrack: 0/20).

[ebuild  N     ] app-arch/lz4-1.10.0-r1:0/1.10.0-meson::gentoo  USE="-static-libs -test" 379 KiB
[ebuild  N     ] dev-db/mysql-connector-c-8.0.41-r1:0/21::gentoo  USE="-ldap -static-libs" 477295 KiB
[ebuild  N     ] dev-db/mysql++-3.3.0:0/3::gentoo  USE="-doc" 4527 KiB

Total: 3 packages (3 new), Size of downloads: 482200 KiB