Advice about the technicalities of moving a flight

I want to move my flight from CHO to ORD to an earlier flight (9am). For clear context I’m united silver.

Currently it is asking for about 14k miles to move it which is lame because that’s basically what I paid for with the flight and I’m saving up for a Europe trip. I know it’s a drop in the bucket but I’m a poor resident haha.

I am United silver - and am able within 24 hours to switch flights for free within the same fare class.

Now I got these tickets for cheap and am in the XN fare class (operated by united express). I have had issues waiting in the past with them saying there are no longer tickets available in my same class. Right now first class is wide open - there are about half economy plus / economy seats open.

Do I …

1) wait till 24 hours and risk there not being open seats in my fare class since I definitely paid for a cheap ticket originally.

2) try that, if it fails go early as “standby” which is free? Correct me if I’m wrong.

3) or suck it up and pay the 13k miles tomorrow.