I once ripped up all the muscles on either end of my right hamstring waterskiing and crushed my L4 disc later the same year, so I know something about sciatic nerve pain. I dealt with it for years but recurring painful episodes were never related to cycling

I don’t get the advice about the saddle size. I get that weight loss could affect your contact points and you might address that, but your sit bones don’t move. My saddle preference has evolved with injury and age but never the size

Maybe you were on the wrong size before and piriformis syndrome just made that clear

So what changed six months ago?