I haven't played 40K but have always been curious about it. Watching this thread with interest. I've always thought I might enjoy hex-based games a little more, but haven't had occasion to try them either.

Yeah, from what I know about war games...They're pricy... And you'll probably be spending money from now until the near future... Unfortunately, I do not have as much experience, either, so... Their's that...

I used to play Dawn of War, a Warhammer 40K real time strategy.
The original game came with 4 playable races, though only a single player campaign for the space marines.
The races were Space marines, Orks, Chaos, and Eldar.
Expansions came with other campaigns and more races.
I still enjoy listening to quotes of some of the characters.
The space marines and Eldar were my favorite to play.
Here are some quotes from the space marine librarian who during the single player campaign became corrupted by Chaos.
https://www.youtube.com/watch?v=rf_3ZTp4eG4
Some of my favorites are:
"Hope is the first step on the road to disappointment."
"Knowledge is power, hide it well."
"An open mind is like a fortress with its gates unbarred and unguarded."
"There is no such thing as innocence, only degrees of guilt."

And from the space marine Force Commander, which is a hero unit:
https://www.youtube.com/watch?v=Qgs29veFrdE
"Walk softly, and carry a big gun."

And from the Eldar Banshees, which were a basic infantry unit:
https://www.youtube.com/watch?v=dmR4I94qpTg
"Many are called, few survive."

And from the Eldar Farseer, which is the primary hero character for the Eldar:
https://www.youtube.com/watch?v=PcR2_N3WHfM
"Orks approach! They are a cancer, we are the cure."

I played a ton of Warcraft, Warcraft 2, and StarCraft when I was younger.
A few things I liked about Dawn of War that set it apart from those, besides its very unique set of races, culture, and history;
were that it let you hold shift to give a sequence of commands, like telling a peasant to first repair a building, then build a power generator, then build a barracks.
And squads not only had health, but also morale, which meant the enemy could focus on depleting your morale rather than your health to get your squad to flee and give up cover, also taking more damage in their fear, which provided an alternate strategy.
And it had you train squads of units, rather than individual units.
A squad could be reinforced with additional units to make it stronger, or equipped with different weaponry to make it more effective against heavy armor, vehicles, or morale.
I think squads are an especially good idea for an audio RTS, since it is important to keep the number of unit sounds on the map low so players are not overwhelmed by too much noise, and so they can manage commanding them individually.
And it had terrain that acted as light, medium, or heavy cover, as a better defensive position for your squad.

I wish I could play an audio RTS with some of the same voice acting and campaigns.
I would also enjoy reading more about each race and unit, or campaigns and lore.