There is one thing you should know ESP32 is a chip, it is quite powerful but it has its limits.
If you are planning to build a base station and you plan to leave it as an open station so that anyone can access it (you, your neighbors, and even strangers who want to use your base station), the number can be up to hundreds of concurrent users, then you will face congestion due to lack of bandwidth.
At this point you will need to build a Base station with ESP32/ESPrtk and upload the RTCM data to free NTRIP services like Rtk2go or Centipede.
You can read more here:
https://discourse.agopengps.com/t/px1122r-f9p-esp32-trimble-topcon-john-deere-ntrip-basestation-esprtk-project/4954/
Conversely, if you want to have a station with concurrent connections (users) < 10 and permissions to manage accounts, track user locations, track statuses, block connections, and so on. …
Then you will probably need your own NTRIP CASTER server.
There are some software running on the computer such as RTKLIB, SNIP… that support NTRIP CASTER.
ESP32 supports 10 connections at once if you want to use it as one
NTRIP CASTER.
And this topic is about NTRIP CASTER with ESP32.
https://discourse.agopengps.com/t/diy-rtk-base-ntrip-caster-cors-server-with-esp32-and-free-ddns-provider-f9p-px1122r/7145/
Also, where are you?
Building your own server will also help you have more stable connections as you won’t depend on 3rd party servers especially if you are on another continent and too far away from rtk2go.
(A war situation, a power outage, a low PING, or when problems with the stability of intercontinental internet fiber optic lines are something to worry about, although these are likely to have less of an effect and not often ).