I've found Nextcloud to be fantastic, its why I started self hosting.
Ive run Nextcloud on a Pi4B with 4GB ram & external HDD with just one user. I also sync Joplin notes, which I use constantly. Additionally used Collabora Office on the phone for syncing office docs. i was happy with this set up for a long time, had no issues really, synced between a couple of desktops & a phone.
Eventually treated myself to a Pi5 8GB ram with NVMe & an Argon fanless case. Main reason for upgrade was an additional Nextcloud need - to share holiday/trip/event photos with multiple non tech savvy older family members via the Memories plug in. This set up has been absolutely rock solid, absolutely no issues & for my needs has been blazing fast. Memories is great too for quick & easy sharing whilst away. The family members love it (Nextcloud is exposed behind Nginx Proxy Manager, I send them a read only public link for Memories)
As they are quite intensive I recently migrated Immich & Paperless from Pi4B 4GB to a Beelink EQ14 but I see no reason at all to migrate Nextcloud from the Pi5.