Lecithin is not a protein or a phytoestrogen. Phytoestrogens, aka isoflavones, are not proteins. Therefore any product containing soy lecithin won’t have isoflavones/phytoestrogens. A soy protein powder wouldn’t necessarily have them either, but it’s possible some trace amounts would slip through in processing.
To get phytoestrogens from soy, you basically have to eat whole soy products: tofu, etc.
So don’t worry about the soy lecithin in your whey powder.
By the way, there’s also no evidence that eating soy with phytoestrogens will drop your T, if that’s what you’re worried about.
Clinical studies show no effects of soy protein or isoflavones on reproductive hormones in men: results of a meta-analysis. - PubMed - NCBI