What works best for me is the couch stretch and the samson stretch with banded distraction. Those two exercises, specifically, have helped immensely and have given me terminal knee extension where I had none

I also had (unbeknownst to me) quad adhesions that weren’t allowing my quads to stretch to full capacity that were also keeping things too tight…once they popped themselves loose, I had more range of motion

I spend about 4 minutes per side in the samson stretch really squeezing my glute and pressing my hip forward and 4-6 minutes per side in the couch stretch doing the same on a daily basis. Making my hip flexors, quads and hamstrings more mobile has really taken the stress off of my knees and lower back. Good luck to you!