What are good exercises for knee pain?

Is it because I overexerted myself with intense exercise to lose the weight gained after childbirth? Since having my second child and doing diet exercises, my knees have been hurting so much.

I rode the bike because I heard it doesn't strain the knees, but actually, my knees feel more painful after riding the bike than before.

So, I generally try not to ride my bike too often.

The worst pain occurs when I stand up from sitting, and it's difficult to fully straighten my knee. ㅠ

I need to keep dieting, and I can't avoid exercising, so I keep moving... mainly focusing on walking.

At least I am losing weight, so I think the pain has decreased a lot compared to before, but I feel like it's a day when I overexerted myself a little.

I have a fever in the evening and my knees are hurting again.

Should I avoid exercising since one knee is more painful?

Since physical therapy was only at that time, I think I need to do exercises that don't put strain on my knees fundamentally...

What kind of exercises do people with knee problems usually do?

I just can't help but do lower body exercises with Javi ㅠ