Synching is for syncing your files across several devices of yours. CryptPad is for working with other people, possibly at the same time on the same document.
The tools donc comapte, the needs are very different, and you might find them both useful in different situations.
It seems to me syncthing simply doesn't need anything more, you just use the desktop application of your choice for editing your documents.
And yes, you are kinda locked into CryptPad if you don't export your documents as you go. The server not having your documents at a central place and all the documents having different decryption keys means it's hard to provide a simple "take out" zip export. I guess some automation tool accessing your browser profile could be built to help with this.
The problem is cryptpad pretends to solve the problem with its "drive", but it's just a (not very) fancy browser for your documents. I can't make a folder with a cryptpad document in it and also all the reference material I want to use. Or any other workflow that involves multiple kinds of files of different types. Manually copying over everything between cryptpad and syncthing is a consistency nightmare.
We never pretended the drive has local syncing. The drive is extremely useful for people to organize their documents inside CryptPad.
It is possible to create folders with any file types in it. Shared folders can be also created.
The workflow you describe with syncthing involves local synching.
We are not saying that syncing locally is not interesting. It's just a lot more work on top of the editor work, the online sharing, the e2ee, etc.. We work with the capacity we have. Also as I said, syncing opens the door to version compatibility issues, risks of mistakenly deleting data of your drive and high volume just for storage. This means for our hosting service (cryptpad.fr) management of much higher volumes. We are not even sure the 1gb free storage policy is sustainable for that use case. But we are working on a path towards this as we have plans for a CryptPad API.
The tools donc comapte, the needs are very different, and you might find them both useful in different situations.
It seems to me syncthing simply doesn't need anything more, you just use the desktop application of your choice for editing your documents.
And yes, you are kinda locked into CryptPad if you don't export your documents as you go. The server not having your documents at a central place and all the documents having different decryption keys means it's hard to provide a simple "take out" zip export. I guess some automation tool accessing your browser profile could be built to help with this.