The only thing that I might suggest is possibly teasing Kyle a bit more when he says a “millennial phrase.” You have a done good job with it before, and I think it’s really funny when you mock him for being a millennial, avocados etc. I am a millennial, but I find it really funny when you call him out a bit for his phrases. I think this will appeal to your older audience as well because it kind of forces Kyle to explain or defend himself. I think a bit more of this type of banter would appeal to some of the people that have tuned out because they feel that Kyle’s millennial phrases go unchecked.
I don’t want you or Kyle to change who you are, but engaging in friendly mocking/debate is good radio, and it allows both sides to be presented. For example, if Kyle says something like “this penguins got murked up,” you could come back at him with something like “what’s ‘murked?’ That sounds really cool when you say it. Did a Migo use that in a bar on a fire track?” Obviously, you will think of a much more entertaining and hilarious comeback than what I just offered, but I think that forcing Kyle to explain himself more will show that you aren’t just trying to be a “millennial show” that is solely trying to be snarky/cater to Twitter