Hi, OP of that post here.

Keystone mount was correctly identifed here: https://reddit.com/r/amateurradio/comments/12ysnt6/_/jhps6mp

RJ45 Keystone Coupler: https://www.amazon.com/dp/B075ZPGV1H?ref_=cm_sw_r_apin_dp_38Q7KXDCHTV0V15VMHQP

Few pieces of advice:

• Buy two or three of the mounts as the clips break easy and super glue doesnt bond well
• If you rotate the coupler in wrong and can’t get it out, dremel the clip off and get one of the other 24 you have

Hope that helps.