Chet;
We all loose mobility/range of motion in different ways and amounts as we age. This depends on our injury history and genetics largely. Hence my lack of specific mobility exercises. However you hit upon what is probably the best mobility routine and that’s yoga.
Yoga is a huge area though. If you are not well versed in yoga I recommend finding the poses and movements that seem to target the areas that you find most limited in mobility and range of motion. I have developed my own modified little routine that works my special spots.
Here is one of my main mobility and range of motion routines. I usually do this 2x/day and man has it made a difference to my ankle, knee and hip range of motion. I start all my strength workout with this. Plus it feels really good for my lower back which is kind of a mess. https://www.youtube.com/watch?v=lbozu0DPcYI&t=86s
You need to experiment. But be proactive with this and it will pay off.
Scott