I'm urinary incontinent too and I use Abena X Plus Diapers from xpmedical.com
https://www.xpmedical.com/briefs/abena-briefs they can hold a lot of urine and can stand up to all day wearing without changing if need be.
They're a little pricey but well worth the cost of the diapers. They also ship in plain boxes with no markings as to what the box has in it.
No one will know that you ordered diapers.