Not possible to be robust unfortunately due to low level SSD architecture[1] and other reasons:

https://nitter.net/GrapheneOS/status/2082153517234676150#m

[1] https://veracrypt.io/en/Trim%20Operation.html

https://veracrypt.io/en/Wear-Leveling.html

That partition will always be obviously out of date and obviously not the main partition.