Crt Clock Schematic Access
Electrostatic deflection requires high voltage (50V–300V) on the plates but very little current . Magnetic deflection requires low voltage but high current and bulky yoke drivers. Most DIY CRT Clock schematics are electrostatic.
The CRT heater requires a low voltage, typically 6.3V, provided by a regulator like the Essential Components List #939 Oscilloscope Clock using a ESP32 Crt Clock Schematic
Do not use a 555 timer into a MOSFET for this. Royer topology is self-resonant and much cleaner for clock applications. Crt Clock Schematic