is there a way to unlock an iphone 6S+ that still has my data on it, without losing everything.

I found my old iphone 6S+ in a closet I am cleaning out. I take good care of my phones and it was even put away in the original box. it turns on and charges up just fine.

The problem is I have no idea what my passcode was.

Plus I have no idea when or if it was backed up last and I don't want to lose any pictures of a significant other that has passed away.

Dose anyone have any suggestions that won't cause me to lose everything on the phone?