It's not so much about the value of bitcoin that you're trying to send, it' due to the number of inputs that you're trying to send.  If you received a lot of transactions to one specific address you may not be able to send all the funds held in that address in one transaction.  You would have to use the "Coin Control" tab to select a few inputs at a time.

Alternately, you could install bitcoin core (no pruning) and let it sync with the blockchain, then import the private key of the address with a ton of transactions.  Bitcoin core shouldn't have any trouble combining all the inputs into one transaction.