Bitcoin is constantly increasing its popularity, it is becoming more familiar to people and its acceptance is increasing, so its foundation is likely to be much stronger in the coming future. But ultimately we should hold it for the long term and 10-20 years is definitely a reasonable time for this, if we can consistently invest and hold Bitcoin for this period, then we can definitely make significant positive returns from it. But ultimately what we have to remember is that there will be uncertainty, everything depends on uncertainty, even if we continue to invest and hold effectively, in the end we will definitely not get any guaranteed chance of success.
Its quite long time holding bitcoin up to 10-20 years later and we miss many great opportunity to sell bitcoin at higher price, I don't have high ambition for holding long term but if get an opportunity will sell bitcoin and buyback later with more lower price. Bitcoin pattern if hit higher price don't hold more long term and take opportunity during bitcoin touch new higher price to sell and accumulate much profit by selling to buy back later when price dropping.
If hold for long term we miss moment to sell bitcoin at higher price and get an opportunity accumulate bitcoin at lower price, did you learn how the pattern bitcoin last year after hitting new ATH price and right now drop more than 40%?