There is a specific pre-existing condition eexclusion in the policy summary cut & pasted above.
As one might imagine, nobody would purchase insurance until after an unfortunate event has occurred if they could wait.
Rather than relying just on CC's, OP should also look at homeowners (which sometimes has a few extra coverages) and any other insurance policies as well as anything his employer has for work-related travel because some of those policies provide coverage for certain non-work related travel as well. I would simply scour anything that exists.