Pricing is pretty high for business $10.99/month vs Google Workspace starter at $6/month (which has many more features). Maybe a cheaper drive-only plan would be a good option.
Pricing of an encrypted provider cannot be competitive with an unencrypted provider, as with encrypted storage, you're not always able to deduplicate or compress file in a way non-encrypted providers can.
Additionally, Proton has their main datacenter in Switzerland, with backup sites in Germany, which has a higher power, cooling and labors costs.
Hence why pricing wise, a competition on prices from unencrypted storage providers won't ever work.