I hear that with BTC arbitrage, people make 20-25% per year.
What is the best way to do that?
The best way is not trading or arbitraging.
You can hold your bitcoins and see it helps you to gain massive ROI.
https://casebitcoin.com/1 year ROI: +102%
2 year ROI: -2%
3 year ROI: +11%
4 year ROI: +379%
5 year ROI: +1,067%
6 year ROI: +275%
7 year ROI: +5,007%
With 4 year or 7 year of holding, you will have very high ROI that gives you more than 20% or 25% gain each year.