It's really astonishing that FTP is being deprecated with no adequate replacement. SFTP is not a replacement because it necessarily piggybacks on SSH and it's not reasonable to provide it as a standalone service, HTTP PUT/WebDav is not a replacement because it's not a file transfer protocol but a bag on the side of a web server and it has significant performance problems compared to FTP for the basic function of "uploading a file", SCP is the same problem as SFTP but worse...
As someone who supports file transfers for like 70% of my job responsibilities: SFTP is the best option even if it is imperfect.
FTPS, if it weren't needlessly complicated (we have like 3 ftps connections at work and they all give us production problems regularly) has potential but it's really just introducing certificates into a protocol that wasn't designed for it.