There are chain joining links one can get. Yes, it might end up the so-called weak link, but as the chain most folk use has a fairly wide performance margin, and you would only be putting out that much such as to bring the new chain and joiner into play very seldom, and usually good conditions, (because you would not choose to anchor in a very deep place unless the forecast was good, right?), so it may end up an academic issue only.
https://www.google.com.au/search?q=c...HeyHDD8QsAQIJg