Would you still recommend to friends to buy Bitcoin?

I used to recommend it because it is simply "the biggest crypto currency," so what can possibly go too wrong?

However, now with Microstrategy looking more and more like a ponzi I'm worried that once they blow up I might regret my endorsement

Why microstrategy is a looking as a ponzi?
Whould you recommend buying gold? The same hold for Bitcoin. Speculators are everywhere but the fundamentals are strong.

If so much of the price action of last few years is due to microstrategy's buying, it's blowup will likely lead to price drop

your question was about buying bitcoin, not Microstrategy's shares...

https://news.kiwistand.com/stories/Bitcoin-Treasury-Companies-Are-Bubbles?index=0x6868e0406d5fac50c6dd767e96c6af6625a17d4f109fc5605120181897f5b53fe25e0a09