Afaik mosquitoes don’t really contribute ecologically. They are just nuisance.
Bats eat tons of mosquitoes. Some outfits encourage and help people set up bat friendly enclosures to deal with local mosquito problems.
Lets face it, if the same Malaria mortality rate happened in the West, we wouldn't (and historically didn't) wait for vaccines - we'd pave over an entire ecosystem if we had to. We'd do the same even if we had the same death rate as the group that got vaccinated.
Even rogue nanoswarms are less worrisome than mosquitos as a vector.