memorization as only backup == bad (for obvious reasons)
*25th word (or seed encryption) == bad (it essentially creates the equivalent of a 2of2 multi sig increasing the risk of loss of funds)
other methods of seed obfuscation == bad (no increase in security and increase chance of loss of funds)
just store the 12/24 words in the most unobfuscated way possible, in a durable offline medium and just worry about keeping that safe. Do as many copy backups as you can reasonably keep safe and need.
Everyone should read this https://blog.lopp.net/how-to-back-up-a-seed-phrase/ by Jameson Lopp
TLDR:
*25th word (or seed encryption) == bad (it essentially creates the equivalent of a 2of2 multi sig increasing the risk of loss of funds)
For me nothing beats safu.ninja for a single sig.