I have used the danish product unipak which is simply hemp fibre and an oily paste to bind it. It is easy to apply, easy to remove and 100% watertight and approved for used with foodstuffs. It is the standard plumbing solution in Scandinavia and has been in use for as long as I can remember. Better sealing than PTFE tape and food safe. It works on brass, steel and plastic joints. I use this and recommend it.
https://unipak.dk/en/catalogue/thread/jointing-compounds/unipak
You can get it online at any Scandinavian plumbing supplies website
