Real time nick (systemd timer version)

tgnick.service

[Unit]
Description=Telegram nickname updater
After=network-online.target

[Service]
User=yourname
Type=oneshot
WorkingDirectory=/path/to/updater
ExecStart=/path/to/updater/venv/bin/python3 /path/to/updater/updater.py

tgnick.timer

[Unit]
Description=Update Telegram nickname every minute

[Timer]
OnCalendar=*:0/1
Persistent=true

[Install]
WantedBy=timers.target

updater.py

#!/usr/bin/env python3
# -*- encoding: utf-8 -*-

import time

FIRST_NAME = '咸鱼'
LAST_NAME = '@ %H:%M GMT' # Follow the rules of Python's strftime

START_TIME = time.time()

from pyrogram import Client, api

def update_name(client):
    client.send(
        api.functions.account.UpdateProfile(
            first_name=time.strftime(FIRST_NAME, time.gmtime()),
            last_name=time.strftime(LAST_NAME, time.gmtime())
        )
    )
    print('>>> Name updated.')

if __name__ == '__main__':
    app = Client("real-time-nick")
    with app:
        update_name(app)
    exit(0)