I'm looking at buying a UA business ticket, with $ not miles, for travel in April. Given covid uncertainties, I'd like it to be refundable. This is from transcon LAX-EWR round trip in polaris on 787-10. I have a united explorer card. Some questions:

1. I can't yet figure out how to buy a refundable business ticket or figure out how much it would cost. Can anyone help?
2. UA currently offers no change fees because of covid. If I can't refund a standard business ticket, can I change to whatever the cheapest united flight is, get credit for the difference, and then cancel the cheap flight and lose just that much?
3. I'm not very experienced here, so I should ask: What else should I be asking? Or what other ideas might there be to deal with this situation?