What Type Of Backups Is Time Machine Really Suited For?

When the Time Machine drive is full and deletes the oldest stuff to make room, does it take into consideration whether you have only one backup of a file?
Example:
Time Machine’s oldest backup is on 1/1/2021, and on that date it backed up files A, B, and C.
As time goes on, only file A is edited, the latest edit occurring yesterday. So now the latest backup of file A is from yesterday, but the latest and only backup of files B and C are from 1/1/2021. When Time Machine goes to perform its next backup, it sees the drive doesn’t have enough space, so it has to make space. Does it delete files A, B, and C from 1/1/2021? Or does it just delete file A from 1/1/2021?
I’m trying to determine whether Time Machine is suited for long-term, archival, or permanent backups. If not, please let me know if there is a method that is better suited for “forever” backups, and how that is done and maintained.
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Eric