TRON network fees are high. It will take a nice part of your output amount if you send a small amount like $100.

1000 USDT (tron) to USDT (eth) becomes 982 USDT (around 1,7% fee). If you assume the TRON fee is $6, that's a final fee of 1,2%.
How high do you mean and which Exchange is high? USDT withdrawals from many CEXs for the TRON network are no more than $2.
And let's compare it with its competitors:
CCE Cash: Withdrawal of $30 will be $29.33 = 2.2%
b1eXch: Withdrawal of $30 will be $25.77 = 14%
Dex Fo: Withdrawal of $30 will be $20.8 = 30%
CCE Cash: Withdrawal of $100 will be $99 = 1%
b1eXch: Withdrawal of $100 will be $95 = 5%
Dex Fo: Withdrawal of $100 will be $90 = 10%
CCE Cash: Withdrawal of $1000 will be $995.45 = 0.45%
b1eXch: Withdrawal of $1000 will be $984.88 = 1.5%
Dex Fo: Withdrawal of $1000 will be $982 = 1.7%
From this data we know which is the most expensive.



Right now, the fee for transferring TRC-20 tokens, including USDT, on the Tron network is 6.4285 TRX ($2.08). So, the higher the TRX price, the higher this fee will be in dollar terms. As for CEXs, they can clearly afford to set lower and more competitive fees for users, since many of them likely have plenty of Energy and Bandwidth in their hot wallets, which allows them to effectively avoid or minimize TRX spending on TRC-20 transfers.
As for DEF, I agree that such large USDT losses when transferring from one network to another are abnormal. But as far as I understand, this only happens when using chain mode, which implies that the exchange takes place through a third party, and if I’m not mistaken, the total exchange fee can be higher due to additional routing and conversion steps.