There are several new-ish approaches to injectionmoulding thse days.

You can use a 3d printer capable of printing with PEEK. And actually print injection moulds.

Then there is a new system whereby you print the mould with a high temp resin using a resin machine and after injecting the plastic the resin mould is dissolved.

That's really - curently - only suitbale for small items and fairly short production runs.

A good PEEK capable printer will run you around £5-10,000.
So you've essentially got your money back after two moulds.
PEEK is considered as a replacement for metals like aluminium. https://en.wikipedia.org/wiki/Polyether_ether_ketone

But standard fdm should be fine :-)