Hi has anyone here used Tiger Brokers? May I ask if there are any conversion fees when converting SGD to USD and vice versa? And am I able to keep my cash in terms of USD after I sell my US stocks?

I have been using Saxo for some time but I realized the conversion fees are really eating into my profits. For Tiger Brokers can I store multiple currencies in 1 account? I would like to just buy USD for US markets, and just keep trading in terms of USD for US markets