IIRC the seed is only viewable the one time, and the "backups" are encrypted with it, therefore backups are useless without it being recorded separately

I say "backup" because there is no backup in Lightning perse, only the latest state, and the pointers to signal force closes to your peers. Only the latest version of node state is useful, and trying to use an old copy may cause you to lose channel funds due to justice transactions resultant of broadcasting obsolete state

Restoring from backup is meant to get your funds back to you on-chain, you shouldn't re-use a node to create new channels after recovering it: https://github.com/lightningnetwork/lnd/blob/master/docs/recovery.md

You can delete the data for lnd by nuking its storage, where that is varies by OS:

; The default location for this file is in ~/.lnd/lnd.conf on POSIX OSes,
; $LOCALAPPDATA/Lnd/lnd.conf on Windows,
; ~/Library/Application Support/Lnd/lnd.conf on Mac OS
; The default location of this file can be overwritten by specifying the
; --configfile= flag when starting lnd.

Once storage is deleted, if you start LND it'll go through the initialize/recovery prompting as if it were new

If you have meaningful funds in a node and need help with recovery the best move is nothing until getting some support, an error can cost you.