Ich hatte es am Anfang auch mit dem + versucht, bin jetzt aber auf catchall umgestiegen, hauptsächlich weil die +-Adressierung nicht überall durchgängig funktioniert. So hab ich auch pro Account eine eindeutige Mailadresse, weiß woher Spam kommt bzw. welcher Anbieter sie geleakt hat, und verwalte es mit einem Passwort-Manager. Bisher läuft's gut :)

Maybe we can try this new thing "Jumanji" next :-O

Maybe strings can get some usefull output too?

Same Here, exactly the same :) have fun you two!

I had Setup nextcloud for this scenario for two weddings now - share a folder, create a QR code for the URL and print that on flyers, cards, whatever is handed out to the guests. Folder is set to upload only, so it's much like a "just place your files here"-link. Add another share link with read/write permissions to the same folder if needed, create a second QR code and you're good to go :-)
Depending on what permissions the "guests" should have, keep in mind that person a could delete person B's photos (un-) intentionally, so I would go for read only access if you have like inexperienced or old users, that don't know technology so well.