Hi dhruvsheth-ai...
I've not used virtual environment to run my programs, I'm able to run on default system environment...
Co-incidently, I have tried all ways (4) from a different article from same website except the crontab
--> https://www.dexterindustries.com/howto/run-a-program-on-your-raspberry-pi-at-startup/
The link you shared is from same website, but article is specific to crontab...
https://www.dexterindustries.com/howto/auto-run-python-programs-on-the-raspberry-pi/
I'll give crontab method a shot and update you,,,, probably it should work...
Thanks & Best Regards,
Ram