If it were me I'd take a different approach. What you are really trying to do is avoid an INR case, no?
You COULD try to monkey with or manipulate the eBay system to your advantage OR you could manage the expectations of your buyer. AKA provide good customer service.
What your could do is to ship it immediately (get an acceptance scan) and contact the buyer. Thank them for the purchase. Tell them that you shipped their item at XXX Date and YYYTime (from the receipt you get at USPS). Then report to them the system delays with USPS due to COVID and worker shortages, holiday volumes, etc. Pledge to keep an eye on the tracking and progress of their package and do it. If things get delayed you can start the Missing Mail process (2 steps) with the USPS and report those actions to the buyer.
If you want to be a "ship it & forget it" kind of seller in this current climate, INR cases will find you. Seems like the proactive sellers are having many fewer (if any) INR cases because they have communicated with their buyers.
This is just something you can do to help yourself rather than relying on eBay processes to 'do something."
