Best glide path for endo in government office ?

Hi, I work in a government office and do endo!! A lot of these cases recently I put a 10 file in and I struggle to get to apex

I try coronal flare with sx first and then place the 10 or 08 but even today it wouldn’t go . So calcified or stuck. Can you guys help me produce a predictable glide path to allow me to reach these canals ?!

Materials I have are 08 ,10,15,20 sx and wave one . What would be your best way to be getting consistently to apex . These are all k files . No d finders or anything like that