More important question is at what range does F35 detect the radar when radar is using that much energy. It is a deterrent but if the F35 can detect and kill your radars from several hundred kilometers that isn't enough for protection on its own. The second matter is electronic warfare, imagine enemy is using F35 alongside multiple powerful EW systems, will radar be able to resist EW while maintaining maximum detection range? But afaik, you do start needing much thicker coating to resist lower frequencies and from quoting thisanalysis [https://www.veryansintv.com/yazar/beyazit-karatas/kose-yazisi/turk-kartali-milli-muharip-ucak-1/] particularly at L band F35 is most detectable although L band will make it difficult to differentiate targets.