The 505-DC2100C-C-ND appears to have been listed earlier this year with the caveat that a manufacturer’s quote is required to order, and would appear to be a successor variant to the DC2100B which is indeed obsolete.
“Quote required” is often an indication that a supplier wants to be selective about the parties to which a product is sold. To engage that process, use the link provided on the product page to submit the requested information.
There are no other eval boards available to my knowledge combining those two particular ICs. If realizing a function is the goal rather than procuring an evaluation board for a particular device, it’s possible that alternatives may be available from stock.