I'll save you some time.
Glucosamine and chrondroiton may have some value for people with osteoarthitis but that's about it. Most knee pathologies do not benefit.
Here is the kitchen sink approach:
1. Walk a lot. Too many runners are "active-sedentary", so they are either putting a lot of stress on their knees or sitting. Your body needs lots of low-intensity exercise to be healthy.
2. Hot yoga once or twice a week. Knee pain has a bunch of theories and is probably multifactorial. "Poor ankle dorsiflexion", "inflexible quads", "inflexible hip flexors", the list goes on. The men who go to yoga pretty much all have stories of some sort of chronic pain that went away or at least became manageable once they started yoga.
3. Bone broths. In poorer times we used to use the whole animal and the only decent way to eat tough cuts of meat is to use wet cooking methods to break down the tendons and connective tissues. It makes for delicious soups and stews, but it is also rich in, well, the things that make up tendons and connective tissues. Some of them your body can make, but many inessential nutrients are really conditionally inessential because not everyone can synthesize adequate amounts, particularly as they age. (you can try supplementing with collagen hydrolosate and calcium hydroxyapetite, but I worry that these supplements may be as-yet unidentified co-factors found in bone broths).
4. Squats and hinges. Muscle imbalances may also play a role, just like flexibility defects. Do 3 sets of squats twice a weak and follow it up with a "hinge" exercise like deadlifts or kettlebell swings. That will give you some balanced lower body strength.