That’s just not true. To the extent lobbyists make donations, they do so in their individual, rather than representative capacity. Look at open secrets’ list of top lobbyists: https://www.opensecrets.org/lobby/top.php?indexType=lb&showY.... They’re not making “large donations.” Some of the top lobbyists contributed nothing. Most a few hundred to a few thousand, which is not out of line for DC residents in that economic stratum generally. In a typical election year, donations by federal registered lobbyists amount to $10-20 million total:
https://www.opensecrets.org/news/2018/01/political-donations.... In 2016, lobbyists contributed just $26 million of the $6,500 million spent in the elections. Lobbyist contributions account for a tiny portion of re-election campaigns, wholly at odds with the idea that money is what gives lobbyists influence.
I think what you're missing is that yes, Joe John working for Microsoft as a lobbyist is not directly donating, but Microsoft is donating to politicians via PACs etc. The notion that a politician is not going to give more weight to a lobbyist employed by their corporate donors is playing dense on purpose.
PACs and SuperPACs are donations made for lobbying purposes. Individual lobbyists may not fork over money, but any real lobbying campaign overall does.