I have a few metal picks including one silver and one gold plated which my brother-in-law gave to me when he gave up guitar.
I never got on with those but, IMO, they were not the right shape for me.
More recently, I purchased a couple of metal picks made from coins:
Apparently, the Feng Shui coin is very good, so I might get one of those to try in the future.
The sixpence is OK, but too small for me. The 5 yen coin is much more comfortable and the hole in the coin helps with grip. Both are a much better shape for me, and are useable for single note lead-line type work.
TBH, I’ve not tried using them for strumming and I suspect, as you do, they may have an impact on the life of the strings.
Cheers,
Keith