You should instead be backing up entire wallet files and restoring them when you need to restore backups, rather than trying to find an individual component of the wallet.
If you insist on using the seed, you need to create a legacy wallet and use the sethdseed command. Then you will get the addresses that you expect. Then you should migrate that to a descriptor wallet. However, after migration, the seed will not be used by the wallet anymore. New descriptors are generated which essentially replace that seed.
so would that mean that a paper wallet can't be done anymore?
what are other solutions that do not imply saving a file?
plus, i read the legacy wallet option is going to be removed from the bitcoin core, so that wouldn't be a long term solution.
i wanted to stamp the hd seed in some metal washers, and this is a bummer.
maybe now i find a solution, then in two year that won't work.
consider i want to do something that would last forever. what would you do?