Problem of Proton Drive is not only in the missing linux client. There is no support of WebDAV that makes integration with many open source tools (like note taking apps or photo management tools) almost impossible. Nextcloud is much better for me. Without a WebDAV (or one of other popular APIs) it looks like an attempt to create “walled garden” with vendor-lock on Proton, imo.
Deepseek collects and process all the data you sent to their LLN even from API calls. It is a no-go for most of businesses applications. For example, OpenAI and Anyhropic do not collect or process anyhow data sent via API and there is an opy-ouy button in their settings that allows to avoid processing of the data sent via UI.