Well first you ammonia hasn't leveled off yet. If you are still doing these WC's every other day and more than 50% at a time then either A) you may have traces of ammonia coming out of your faucet, or B) it's not close enough to being done with the cycle.
Obviously a fish-in cycle is a pain in the rear end. I learned this lesson 5 years with GSP's (green spotted puffers) which are brackish fish. So not only was I doing wc's everyday, but I was adding salt in the water as well.
This has nothing to do with your filter working effectively, this is just nature at it's best. You are waiting for the beneficial bacteria to be able to take the ammonia load and make it 0 within 24 hours.
Waterdrop is correct by saying you aren't doing enough WC's, which would probably be better everyday than every other day. It is rough to do with a bucket, but I always suggest buying a siphon that connects to the sink, it is so worth the money when you aren't killing your back and you are more likely to do WC's more often because they are so much easier.
Obviously you may not want to spend the extra money, but once again this is a complication from not doing the research, and nitrites are just as bad for fish as ammonia is.
I don't know if you could get anyone to help you out, a neighbor, or your son (idk how old he is). Fish can go a little bit longer in between feedings, and to help cut down on the ammonia produced, clean out the food they do not eat within a few minutes.
You may need to keep doing this for another 2 weeks, there is no guarantee, but nitrites do not take as long as ammonia does.
Just be prepared with these readings you may lose your fish suddenly. You are doing as much as you can, but it may not be enough.