I would recommend proton drive as a great replacement if you want something that doesn't need a server
Headphone jacks and small phones
STAR WARS: Squadrons I'd on sale for ยฃ1.75, definitely worth picking up at this price
The closest is nextcloud collectives, tables, tasks and deck
I personally like Nextcloud notes for quick notes and nextcloud collectives for detailed stuff e.g revision. With nextcloud tables and deck it makes a great notion replacement
I would recommend proton drive as a great replacement if you want something that doesn't need a server