Nextcloud on it’s own can’t read images EXIF data so it can’t sort them by date. I’ve tried Memories addon and it seems to work well, except for transcoding movies.

It really mostly depends on if other family members will need to edit the wiki.

• If they’ll be only reading dokuwiki might be best - even a single frontpage with all the info nedded.
• If they will be editing then bookstack is way more friendly for non-technical people as is had a full WYSIWYG editor and you don’t have to bother with markdown.