for lemmy, its pretty straight forward with this bot

https://github.com/programming-dot-dev/rss-bot

for the 'bins, there doesnt exist a direct-to-mbin bot yet (i’ve been workin on it… i suck at logins), in the meantime youd use a lemmy instance as intermediary:

you setup a non-public, localized lemmy instance, have the bot configured for your needs to grab feeds into communities, then subscribe from your 'bin instance.