While The Armchair Dragoons are primarily a hobby-focused site, there's a lot of professional coverage there, including a dedicated sub-forum specifically for pro topics
Additionally, there's a bunch of episodes of the podcast that focus on professional topics, including several with the wargame design program at the US Army Command & General Staff College out at FLKS.
James Sterrett talks about the CGSC wargame design MMAS program
Rex Brynen talks about SWEAT considerations in wargaming
Discussion of the essential books in a wargaming library, including a variety of academic tomes
On Target Sims talks about their work with the UK DSTL, among other things
Matt Caffrey talks about his book "On Wargaming" and the research behind it
Interview with an MMAS student at CGSC
Derby House Principles on Diversity & Inclusion in Professional Wargaming
There are also videos about games & sims for training & learning (classroom use), GUWS students about their wargame design program, and data curation & archiving, among others.
The weekly Tuesday Newsday review always includes a set of links on professional wargaming, too.