There have been a few. I know https://www.hootsuite.com https://www.hootsuite.com is one of those, but does not currently seem updated to support any of the one

There have been a few. I know https://www.hootsuite.com https://www.hootsuite.com is one of those, but does not currently seem updated to support any of the ones you asked about! https://fedica.com/ https://fedica.com/ seems to maybe be a parent company (acquisition?) of Hootsuite. https://buffer.com/publish https://buffer.com/publish I first heard about this ages ago as a way to build a queue of things to put out to Twitter. They likely support Mastodon and LinkedIn now, but probably not yet the others. See https://support.buffer.com/article/567-supported-channels https://support.buffer.com/article/567-supported-channels