This technical article thinks the rumors are a bit overheated:

No, The iPhone 13 Does Not Have Satellite Internet | Band n53 & Globalstar (GSAT) Explained

"Recently rumors cropped up that the iPhone 13 would support Satellite internet. The internet and Apple fan world went into frenzy with all sorts of speculations and tech media publishing many articles. Globalstar, a satellite services business, had their shares soar 90% from mid-August lows. SemiAnalysis is tired of hearing ridiculous fandom regarding satellite capabilities on the next iPhone, so we are going to lay out the technical details.

The source of this rumor is from Ming Chi Kuo, the best Apple supply chain analyst, but others have spun it out of control. The iPhone 13’s modem will support the n53 band. This is nothing by itself. The 3GPP, the standards board for 5G and other telecommunication standards has made it part of the evolving 5G standard. The 3GPP addition of this n53 band (11.25MHz of spectrum 2483.5MHz to 2495MHz) is not for explicit satellite connections, but because Globalstar is targeting it for terrestrial usage...."