Here's my strategy:
Long haul J redemptions on DL suck. I have DM status through 2032, so I have no need to worry about spend in the DL environment. Even before the extension for rollover MQMs, I always churned UA and AA credit cards.

With a little planning you can easily acquire many UA and AA points through sign up bonuses. Both of these airlines have considerably better redemptions for long haul J. Sign up for a Chase UA Personal, Then an AA personal, then a Chase UA Business, then an AA Barclays aviator, then an AA business, etc. If you have a partner who can alternate which SSNs your using also makes it easier to continue to be approved, especially with chase.

I have migrated most of my spend to a generic AMEX card with membership rewards points with transfer partners to look for decent J redemptions.