TGIshabbos
“that’s kind of like a Reform-Judaism type of thing to do, Shehechianu for nearly anything and everything (a birthday, an anniversary, a new job, a graduation etc). It certainly cheapens the beauty and rarity of the bracha.”
I dont care for calling the desire to thank Hashem for something reform.
First of all The examples You cite are rare, birthday, anioversary is once a year each. And most people Don’t get new jobs or graduate often. None of thsoe would cheapen the beauty or rarity of the beracha.
That said, like everything in our lives there are halachos. There is siman in shulchan Aruch OC 223, 225 with halachos of when the beracha is made, including buying new clothes , “keilim” , house and of course fruit. (I didn’t see mention to try to avoid eating too many fruits in order not to cheapen the beracha, in fact the opposite is true many have the minhag on Tu Bishvat to seek out fruit to make shechiyanu)
As to whether the vaccine qualifies as “keilim chadashim” or “good news” is a fair question. Most poskim said no, a few say yes.
as always speak to your LOR