I have been transferring funds between exchanges using LTC as I researched and found that to be the cheapest.
That was still a bit of a hassle, as I had to trade my crypto asset for LTC before transferring over. Sometimes the price of LTC fluctuates and I lose. Not to mention it cost transaction fees for the exchange of crypto assets.
As I explored the option of sending USDT instead, I found the Solana network to be among the options available. It cost close to nothing (0.000005 SOL) to send USDT through the Solana network from one exchange to another.
It is pretty fast too.
I like it better than using the LTC network.
As usual, do your own research too, what I described might not be true by the time you read this.