Is there a portable charger available with enough volts and amp to charge any Tesla car to give it enough power to drive few miles
Yes there is!
YouTuber Tesla Bjørn has been uploading videos of what happens to different EV's when they reach a low state of charge enough that they can no longer move on their own.
He carries out this test on a side road near a DC fast charger which has nearly no traffic at all, but the important thing is he brings the EV's back to life, just enough to move a few miles to the DC fast charger, using an
EcoFlow DELTA Max with a 4 kWh setup. (You can have a 2, 4, or 6 kWh setup with the DELTA Max model).
He has found quite interesting results doing this experiment, as the BMS deals with the very low SOC very differently in each EV.
For example the fat Audi e-tron wouldn't move after receiving nearly 3.6 kWh (after losses) from the EcoFlow. He is also able to see how much lower hidden buffer the battery has (after the vehicle claims 0%) and what user alerts the car shows the driver before killing the powertrain due to lack of power and protection to the high voltage battery.
Anyway, I highly recommend watching
those videos and I've even bought an EcoFlow myself, which I bring with me every road trip I take, (it's very heavy as you might imagine), but fortunately I haven't been able to use it... yet.