Uber

The usual advice that I see is to take a taxi from the regular taxi line. The rates are fixed at 56€ to any location on the Right Bank and 65€ to any location on the Left Bank. You do not say which train station so I am including both fixed rate fares. The one time I tried to take a take from CDG to Paris was with a friend who insisted on Uber and after we could not find our Uber driver and he canceled the ride, we took a taxi. Taxis can use bus lanes and Uber cannot. I had an extremely upsetting cancellation (not at the airport) of a ride in Paris this past March and vowed never to use Uber again in Paris so I might be biased.

beach,
Never used Uber in France, but the general comments I find here suggest the French ride share service, Bolt, is more reliable. That being said, from the airport I would definitely take a taxi from the official taxi rank. Fixed rate for up to 4 and their luggage, faster than autos because they are the only autos that can use the bus lanes. The pickup for rideshares and hired car services are farther than the taxi rank as well. (I don't want to schlepmy bags on the RER and metro...I am too old for that.)
Do not take a taxi from someone who approaches you. Only use the official taxi rank.

I've relied on Uber three or four times over the course of three separate trips, primarily upon arrival either at CDG, Orly or Gare du Nord. At CDG the Uber rendezvous point is fairly easy to locate, less so at Orly. At Gare du Nord it is best to walk a block or two away and locate a local business from which to be picked up. We never had an issue with reliability. The driver from Gare du Nord was quite friendly.

It's unclear why one would use something like Uber rather than a legitimate, regulated taxi service, but I have to chuckle at your reference to "the train station in Paris."

Are you under the impression that there's only one train station in Paris?

Definitely the official Paris Taxi ranks that are just outside the airport. Here’s the link about taxis on the CGD airport website:
https://www.parisaeroport.fr/en/passengers/transport-parking/taxi/cdg