Python Gunicorn with Gevent workers very slow than pure flask for time.localtime

I have a controller that's very slow when running in Gunicorn/Gevent (21sec) over pure Flask (5s)

Upon profiling there are 300K calls to Python's built-in method time.localtime. Here's a simplified controller that also shows this behavior

import time
def my_time():
    time.localtime()


@app.route('/my_test', methods=['GET'])
def my_test():
    """
    Test endpoint
    """
    for i in range(326457):
        my_time()
    return 'OK'

Profile output from running pure Flask

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
   326457    0.204    0.000    0.387    0.000 __init__.py:23(my_time)
   326457    0.183    0.000    0.183    0.000 {built-in method time.localtime}
   326457    0.010    0.000    0.010    0.000 {method 'disable' of '_lsprof.Profiler' objects}
        0    0.000             0.000          profile:0(profiler)

Profile output w/ Gevent/Gunicorn. Gunicorn server settings gunicorn --workers=2 --threads=5 --timeout=300 --graceful-timeout=300 --worker-connections=100 --worker-class=gevent -b :8080 main:app

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
   326457    0.226    0.000   15.784    0.000 __init__.py:23(my_time)
   326457   15.557    0.000   15.557    0.000 {built-in method time.localtime}
   326457    0.016    0.000    0.016    0.000 {method 'disable' of '_lsprof.Profiler' objects}
        0    0.000             0.000          profile:0(profiler)

What's causing time.localtime to take over 15s with Gunicorn/Gevent?

Versions

Python 3.6
gevent==22.10.2
gunicorn==20.1.0