@brush439 I see your problem with water changes. I have a few temperate tanks and have had similar responses to cold water changes.
As I haven;t had a problem with these pests in my tank I had a look and found this information:-
https://content.ces.ncsu.edu/biology-and-control-of-non-biting-aquatic-midgesFor the time being I would suggest that you try the sticky strips to catch flying adults.
Look for the jelly lumps that are the egg masses, and remove them from the surface area of your tank. Hopefully these will be close enough to the surface to avoid disturbing your fry in the tank.
Increase the surface water movement, which I'm guessing makes it difficult for the adults to lay eggs.
This sort of low impact approach will probably take a lot longer to help your situation, but will leave the rest of your tank undisturbed.
The information indicated that the midges are attracted to water with a lot of nutrients. What are your current water parameters?
If you are prepared to try some water changes you could try removing water from the middle of the tank, to avoid disturbing the fry on the sides. You could try using a jug if you don't want to use a syphon. Or perhaps use something over the syphon (ladies tights perhaps, or similar) to avoid sucking up fish fry.
Bring the new water to the right temperature before adding it to the tank - you can use tap water if you have a combi-boiler, or water from the kettle.
@fcmf has mentioned the possible impact of air movement, so perhaps if you run a fan near the tank the air flow will blow the midges away from the tank and stop them from being able to lay eggs.
It may be a case of low impact controls and constant monitoring for the time being.
Best of luck and please keep us updated.