The old myth that running is bad for your knees. It isn’t unless you have a condition. What you may not have is tendons ready for the effort or the right supporting muscles. These can be worked on.
for running, lowering your pace to "just above walking" speed will help you run much longer, and develop the muscles needed
This is paid but also very good. https://uphillathlete.com/product/at-home-strength-training-...
The main thing 90% of people will benefit from is learning to activate their glutes, then strengthening their glutes. Clamshells are a great place to start.
A lot of people hurt their knees because their glutes don’t activate and are weak from sitting all day. This forces them to become quad dominate, which puts more strain on the knees.
1. Run slower. Then run slower again.
2. Run a shorter distance/time and gradually build up over time (weeks/months).
3. Lose weight (on average, people are overweight). If you're underweight, then eat more.