“Who says one should skip all the hachanos, and just say words with minimal kavanah in order to beet chatzos? It can be not even considered davening.”
After chatzos it’s the afternoon. It’s no longer shacharis, and one cannot daven minchah until half an hour (shaaos zmanios) after chatzos. So it’s stam a bracha levatalah.
“Minimal” kavanah is defined as knowing the words to the first bracha of shemoney esrei.
“It actually says in shulchan aruch if one can’t have kavanah he should not daven”
It says not to daven over again if you didn’t have kavanah by the first bracha, because maybe you won’t have kavanah the second time either, but it does say to continue and have kavanah at least by modim, because some hold that modim is the bracha that’s mea’kev for kavanah
It does NOT say that one shouldn’t daven unless they have total kavanah for the whole or even most of shemoney esrei. The steipler writes that one who knows Hebrew basically always has basic kavanah because they know wbat they’re hearing when they aay the words, even if it’s by rote.
Rw, rav chaim and being omed lifnei hamelech – rav chaim is a daas yochid on this issue and in brisk they indeed are makpid, and daven a fast shemoneh esrei to maintain this kavanah.
They also will always be makpid to daven shacharis in time to make brachos krias shma within the zman krias shema, as is commonly taught in yeshivos.