How do I get my lockscreen option back?

Before making changes, back up your registry by clicking File > Export. This ensures you can restore it if anything goes wrong.

yes still faces this issue sometime

"I faced the same issue once, in my case the lockscreen option was hidden after an update. I just went to Settings > Personalization > Lock screen and checked it from there. If it’s not showing, try switching account or restarting your system, that worked for me."