Max Liquid Flow Possible Across a Pipe

Liquid does not flow across a pipe. It flows through it.

Flow in pipe - Bernoulli equation

<...flow rate will raise to a point till boiling occurs...>

This will not happen if the pressure at one end of the pipe is increasing, because the pressure at each point in the pipe will also increase with it, and boiling temperature is a function of pressure for all fluids that rises with pressure. So the current <...understanding...> is not representative of what happens in the real world.

As a rule of thumb, velocities over 3m/s for liquids and over 10m/s for gases would suggest that the pipe diameter is too small.

Any temperature rise due to fluid friction is miniscule and usually swamped by other effects.

The purpose of a pipe is to convey fluids from one end to the other. If boiling is required, use a heat exchanger instead.