Hmm, I think Jeremia is an irregular case, due to it mostly being a biblical name and I think in biblical texts, they write it as “des Jeremia”. No idea, if that was just en vogue when the bible got translated or what the reason is for that.

But the Duden describes the general rule of thumb for nouns ending in ‘s’ (or similar sounds) by extending them with “-es”: https://www.duden.de/sprachwissen/sprachratgeber/Genitiv-auf-s-oder-es

But “des Matthiases” just sounds archaic.
They also list “des Hans” as the only possible genitive: https://www.duden.de/deklination/substantive/Hans_Mann
So, maybe these are special cases, too…