SAWW

there is certainly no establlished duration for the length of any solat.

it soley resides in the imam and the choice of his sura.

The noblest of mankind however advice that in congreggation, solat should not be carried on for long, while one may elongate the solat in private as in the case of nawafill.

here is a true life story:

A certain young man once led a congreggational prayer for too long.

in the course of a long surah, he suddenly farted and as expected another brother took over the solat and recited a brief sura(guess kaothar,/ wal-asr)

out of ecstasy and a long silent agitation, an elderly man spontaneously exclaimed SIMPLE! (while on solat, at the completion of the brief sura)
it was more like a dream come true. a relief.

Solat should not be seen this way!
i will appreciate a brief/moderate solat for the longer it goes, the farther the mind wanders

you are correct that salah should not be long, rather short or not more than adequately medium lennt of time. and the old man who said simple if it was not an intentioned statement, and it came out in an involuntary way, he does not have to have the badiyyah of 2 sajdah/sajdah sawn because he is covered by the imam.

but am not sure if the unnecessary "talk" is intentional and or long, conscious of it, and voluntarily making it in the salah, if the salah is stil valid, considering that the prohibition of talking in salah is final, "abrogating" earlier possibility of conversation in slah! my statement is similar to when a person thinks that he/she has break the wind, but neither hear the sound nor smell anything, the wudu is still and of course the salah by it are both valid. smelling it even if the sound is silent or hearing the sound, even if there is no smell renders the wudu lost.