I’ve read that it usually goes down to 99% after around 230–250 charge cycles.
That's nonsense. Where did you read this? Apple's documentation states the battery is designed to go up to 1,000 charge cycles before it reaches 80% Maximum Capacity....under ideal conditions. You can confirm here:
iPhone battery and performance - Apple Support
That works out to a 1% decline for every 50 Charge Cycles.
Your battery should be at about 99% after 100 Charge Cycles, so you are doing better than expected.
At 150 Charge Cycles, the battery would be expected to be at about 97%. You get the idea. At 500 Cycles, about 90%
Might be another discussion, but in my opinion Charge Limits are more of a gimmick than anything else. Apple still recommends using Optimized Battery Charging for the best chance at prolonging the life of the battery.
About Charge Limit and Optimized Battery Charging on iPhone - Apple Support
Connect the phone to the power supply at night and leave it connected....all night....every night.
Don't try to babysit the battery. It won't help, and you'll just make yourself nervous if you are checking the battery settings all the time. All that you really need to remember is to replace the battery when the Max Cap drops under 80%.