Bitrot is a myth in modern times. Floppies and cheap-ass tape drives from the 90s had this problem, but anything reasonably modern (GMR) will read what you wrote until mechanical failure.
The key therefore is to verify as you write. Usually, verifying a sample of a few GB will let you know if everything went OK. DO your backups with checksums of some sort. A modern tape drive and backup software will do that automatically, and let you schedule a verify automatically as part of backups (2 TB? That's 1 tape - might want to consider that), though ideally you should verify a tape on a different drive than the one you wrote it on.
For disk-based backups, local or cloud, I strongly recommend archiving to a format with checksums (RAR etc) over some sort of raw file copy. Especially for anything going over the network: RAR a volume/file set locally first, then upload, then test the archive.
If you have a superstitious fear of bitrot, you can always do some random sampling of archive integrity, and keep multiple historical copies of files just in case (e.g., don't just delete backup N-1 when you do backup N, do a rotation scheme).