praying late

for example if the end of zuhr salah is at 1:45 and i start with the 4 sunnah rakats at 1:43 does that mean once i finish at 1:47 and start the 4 fardh rakats mean it’s late?

Yes. Your Sunnah would be in time*, but not your Fard so you would have to specify the intention of qaza. If you knew you were running late, it would be better to skip the 4 Sunnahs and read your Fard. Note that there is no qaza of Sunnahs, so in this case you would read your Fard only. This is OK as long as you don't make missing the Sunnahs a habit.

* Note that this is not the case with Fajr, for which you must send the first salaam before sunrise.