Enabling telnet in the RAX75?

> Anyone know how to enable telnet on the RAX75? [...]

   Not I.  Someone who has touched one might have more/better
information.

> [...] The telnetable.bin trick [...] does not work...

   Netgear appears to have been removing that (undocumented,
unsupported) feature from various models in recent times.  Whether
that's intentional or just another blunder is not obvious.  See, for
example:

      https://community.netgear.com/t5/x/x/m-p/1786837

   It's also possible to provide bad parameters to a telnet-enable
program (bad "admin" credentials, bad/wrong MAC address, ...).