You do not have to run a node to be able to transact.
Correct.
But you will be highly reliant on nodes that your wallet uses for broadcasting your transactions to the network.
FALSE.Running a node does not make you any more or less reliant on other nodes for broadcasting your transactions.
As a medium and large size business you would like to be able to control when you broadcast your txs,
Correct.
be sure that wallets do not falsify your balances,

What balances? What are you talking about? Why wouldn't you know what your own balance is?
That certainly sounds like a
load of nonsense.
So having a node, thus, downloading blockchain is quite necessary.
This isn't a question about downloading the blockchain. This is a question about storing the blockchain. Did you even read this thread before posting your nonsense?