suggest an NPN not afffected by temperature?

All silicon transistors have the same dependency on temperature, there's nothing you
can do by choosing a better device.

What you can do is use a cancelling circuit to subtract the temperature dependence by
using two matched transistors kept at the same temperature. You keep a constant
current through one and then the Vbe difference cancels out.

You can also choose a semiconductor with a much higher bandgap voltage, as the
thermal term subtracts from this, so the larger the bandgap the less the thermal
term proportionally. That means gallium arsenide, silicon carbide or other exotic/expensive
devices.

But unless you say what you are trying to achieve its hard to know how to help.
The cancellation circuit is useful for making analog logarithmic amplifiers and
multipliers, for instance.

It might be that you need feedback in your circuit to linearise it, there are many ways
round a problem if you know the actual goal.