Yes the have fix charges but it changes depending on the network congestion since part of that is paid to the miners. I also thought before that it doesn’t change since binance has its own mining pool but it does change and will reduce if the congestion reduces too
There was a time the fee was 0.0005 BTC. Binance reduced it to 0.0002 BTC. Ordinals came and transaction increased, then Binance increased it to 0.001 BTC this year. OP said the fee is 0.0008 BTC. Amid congestion I was surprised that Binance reduced transaction fee. I went to check and I saw this:
That is almost 2 times of 0.000 8 BTC.
When the mempool was congested in 2020/2021, the withdrawal on Binance was 0.0005 BTC. It took months before Bijance reduced it to 0.0002 BTC when the mempool has been less congested with 1 sat/vbyte getting confirmed, Bijance left it at 0.0005 BTC.
But when the memo becomes congested, Binance will increase the fee asap. But when the mempool become not congested, Binance will not reduced the fee for months that can be more than a year.
Some exchanges are using floating rate, but not Binance. Bijance used a fixed fee that we should not consider to be altered for decrement unless you want to hold on the exchange. And not your key not you coin.
The temporary solution is to just use lightning network on wallets that have their own channel like Muun wallet if the amount is small.