Restoring content from a backup

I recently discovered several important text threads from iMessage have been deleted from my phone. I’ve read the “best” way to get these back is to reset my phone. My phone backs up to iCloud nightly and I have iCloud storage on for my photos as well.

I have an irrational fear that if I reset my phone I won’t be able to get any of my content back. Also, I’m not 100% sure how or when these messages were deleted, so I may need to do multiple restorations to find them.

Questions: if I reset my phone and then restore it from a backup, will I still have all of the content that was on my phone at the time that backup?

Am I able to choose the date I restore my phone to? I have an idea of the date it got deleted but I’m not sure. If I choose the wrong date, can I go through the process and choose a different date?

Thanks in advance for the help! 😜