Hi @anilswipe ,
Maybe you have not installed the linux510-broadcom-wl driver, whether the wifi driver is managed by wl or iwilfi.
I think you should try to install without internet connection before, as is suggested by @nikgnomic in on one of the post you mentioned.
Could you post the output for the terminal commands?:
rfkill list all
dmesg | grep broadcom
journalctl -f -t NetworkManager
Please, also read this post before you copy the output.
‘How to provide good information’
Hope this help,
Regards,