No, he's right. We've got an Edge sport with 22"rims. Came with pirellis and they were junk. We ended up with Michelins. Pretty pricey but worth it.
I found Michelin Premier LTX for $229 a tire/free shipping in 21" and for you, look at the General G-Max AS-05 for $195 a tire next time around.
I’d wait on the ST. I think there is kinks to work out with the new trans vs the proven 6 speed auto that sits in the SHO, fusion sport, edge sport and explorer sport.
LMS has tuned a 2019 ST, but it's putting down a lot less than LMS tune Bob has on his. Like you mentioned, they said it's because it's a new transmission and they are easing into it before going full potato.