Let's discuss the potential effects of stable coins which are bound to usd or eur. We usually use them to avoid the volatility or short bitcoin in a way. There are many stable coins in the last year. By writing threat, I didn't mean issues like tether's issue. I mean, they are not coins, they are just usd and eur.
I don't think stablecoins are a threat to bitcoin at all because they are just safe coins to short bitcoin during harsh market conditions. Stablecoins pose no threat to bitcoin or any altcoins rather threat to each other "stablecoins" in the name of competition.