we can not say for certain if that has begun now.
but it has already begun! in the past months price has risen about 77%, don't you think that huge rise is a "bull run"?
For Bitcoin? Of course not.
A more accurate way to look at things is this: Price crashed by $16,500 (or 84%) and we have retraced a mere 14% of those losses. We haven't even reached the first significant fib retracement level. We are in no man's land. We shouldn't be calling it a bull run when we haven't even recovered lost support levels from 2018.
I'm hoping this is a replay of summer 2015, which was an important part of the bottoming process but wasn't the beginning of a bull run at all. Repeating 2015 would mean we're still going back to the $3,000s.