It's normal for a trader to experience losses because no one can predict the market and even profitable traders agree that. But there are many traders who win a lot in a bullish market rather bearish. Here in crypto, if the market is bullish you can possibly earn multiple of your capital and can be up to 50x or 100x, it happened in year 2021. A lot of traders even newbie traders are getting rich because most of their strat are working since the market direction was always going up. But when bearish came up they disappear.
Aside from that, I only base on my analysis in the chart, I won't say Bitcoin is seasonal.
No matter how good a trader is, even in a bull market, making x50 or x100 in one season is a very big profit. Perhaps some people manage to do this, and it is also not so easy to do when it comes to a large trading deposit.
If you start with a small amount, then it is quite possible that you will allow yourself more risky operations with it and this will bring more profit, but if you start with significant capital, then you will be much more careful with it, and this of course can bring profit, but not like you wrote. For a large capital, even x5-x10 will be considered a very good profit.