Self-hosting hundreds of GBs of data isn't feasible, you also need backups and it's a terrible idea for most people. Hetzner does provide managed Nextcloud instances.
> Self-hosting hundreds of GBs of data isn't feasible
Why wouldn't it be feasible? Storage is cheap, backups are cheap. It's not for everyone, obviously, but for 20 EUR/month you can get a VM with a couple hundred GB of storage and 1TB of backups on a storagebox in hetzner.
Or have a raspberry pi with a 1TB SSD in your home, or both!
The amount of storage isn't the issue unless you're taking about 10++ terabytes.
The things that's interesting is how you're accessing and writing to it - depending on that, it might indeed be infeasible to do everything yourself as an individual.
A "cloud" storage like next cloud with only 1-3 users? That's not gonna become a problem, while the base configuration with backups will likely take you a weekend, it's not that hard.
Why wouldn't it be feasible? Storage is cheap, backups are cheap. It's not for everyone, obviously, but for 20 EUR/month you can get a VM with a couple hundred GB of storage and 1TB of backups on a storagebox in hetzner. Or have a raspberry pi with a 1TB SSD in your home, or both!