What you are looking for are SAM. Strategic Account Managers. These individuals are more flexible to conversations that Strategic Buyers or any other purchasing department. SAMs are reponsible for maintaining existing relationships with key vendors or buyers so that would be a good start for you.
Same thing when you hire, I think you are looking for a SAM :)

Merry Christmas

Usually it's the marketing department that will handle this at mid size companies. I would straight up cold email them to see if they're interested in participating and even if they're not interested, I would ask what would they like to see as a merchant in a product like yours. That way you will learn a lot about what merchants are actually looking for.

Here are some suggestions for approaching large merchants to accept a bank's reward points on their checkout sites:

The key contacts at merchants will typically be in their Business Development, Partnerships/Alliances, or Merchant Services departments.

Start by researching the specific merchant online to identify the executives leading these departments. Try to find someone at the director level or above via their website or LinkedIn.

Cold call or email the targeted executive explaining your bank client's loyalty program and interest in partnering. Mention potential increased customer spending from bank customers redeeming points.

Emphasize any competitive advantage your bank's program offers over others (e.g., a large customer base, higher point values, ease of redemption process).

offer to provide detailed program and customer data to demonstrate potential revenue opportunities for the merchant.

Consider engaging a partnership broker familiar with merchant and bank loyalty programs. They may have existing contacts and be able to help position the opportunity.

Be prepared to discuss potential costs for the merchant to integrate (if any) and revenue sharing models if points are redeemed for purchases.

Follow up proactively and be flexible; the sales cycle may be longer given the internal approvals needed. Offer site visits if they are helpful.

Leveraging an experienced broker and targeting the right executives with compelling customer and revenue data gives you the best chance of success.