Starting a python script from another before it crashes

I'm trying to make some project code I have written, more resilient to crashes, except the circumstances of my previous crashes have all been different. So that I do not have to try and account for every single one, I thought I'd try to get my code to either restart, or execute a copy of itself in place of it and then close itself down gracefully, meaning its replacement, because it's coded identically, would in essence be the same as restarting from the beginning again. The desired result for me would be that while the error resulting circumstances are present, my code would be in a program swap out, or restart loop until such time as it can execute its code normally again....until the next time it faces a similar situation.

To experiment with, I've written two programs. I'm hoping from these examples someone will understand what I am trying to achieve. I want the first script to execute, then start the execute process for the second (in a new terminal) before closing itself down gracefully.

Is this even possible?

Thanks in advance.

first.py

#!/usr/bin/env python
#!/bin/bash
#first.py

import time
import os
import sys
from subprocess import run
import subprocess

thisfile = "first"
#thisfile = "second"

time.sleep(3)
while thisfile == "second":
    print("this is the second file")
    time.sleep(1)
    #os.system("first.py")
    #exec(open("first.py").read())
    #run("python "+"first.py", check=False)
    #import first
    #os.system('python first.py')
    #subprocess.call(" python first.py 1", shell=True)
    os.execv("first.py", sys.argv)
    print("I'm leaving second now")
    break
while thisfile == "first":
    print("this is the first file")
    time.sleep(1)
    #os.system("second.py")
    #exec(open("second.py").read())
    #run("python "+"second.py", check=False)
    #import second
    #os.system('python second.py')
    #subprocess.call(" python second.py 1", shell=True)
    os.execv("second.py", sys.argv)
    print("I'm leaving first now")
    break
time.sleep(1)
sys.exit("Quitting")

second.py (basically a copy of first.py)

#!/usr/bin/env python
#!/bin/bash
#second.py

import time
import os
import sys
from subprocess import run
import subprocess

#thisfile = "first"
thisfile = "second"

time.sleep(3)
while thisfile == "second":
    print("this is the second file")
    time.sleep(1)
    #os.system("first.py")
    #exec(open("first.py").read())
    #run("python "+"first.py", check=False)
    #import first
    #os.system('python first.py')
    #subprocess.call(" python first.py 1", shell=True)
    os.execv("first.py", sys.argv)
    print("I'm leaving second now")
    break
while thisfile == "first":
    print("this is the first file")
    time.sleep(1)
    #os.system("second.py")
    #exec(open("second.py").read())
    #run("python "+"second.py", check=False)
    #import second
    #os.system('python second.py')
    #subprocess.call(" python second.py 1", shell=True)
    os.execv("second.py", sys.argv)
    print("I'm leaving first now")
    break
time.sleep(1)
sys.exit("Quitting")

I have tried quite a few solutions as can be seen with my hashed out lines of code. Nothing so far though has given me the result I am after unfortunately.

source https://stackoverflow.com/questions/74593058/starting-a-python-script-from-another-before-it-crashes