Knee Poly Exchange for Extension Problem

I had TKR 1/26/2023. My knee flexion is fine, but I am stuck at 10 degrees from straight. I have done PT 3 times a week, all recommended exercises and have been using JAS brace for 4 weeks. Orthopedist says nothing I have done or not done is causing my knee not to straighten and recommends (after more healing) a poly exchange in October 2023. I am 77 but very fit and did competitive indoor rowing, cycling, long distance backpacking and hiking so never expected this. Another knee Orthopedist (friend) thinks it is too soon to do a poly exchange, doubts the worth of JAS brace, thinks intensive PT may be too much and also thinks poly exchange to a thinner unit might make my knee too loose. Both Orthopedists are highly qualified and respected. Anyone else have experience with a poly exchange months after TKR?