Didn't CAR (Central African Republic) rolled back its adoption of Bitcoin as legal tender? Only El Salvador remains. Yet, the country made a deal with the IMF that would take a step backwards towards the mass adoption of BTC. The use of the cryptocurrency is now optional, instead of mandatory. All in an effort to help secure a loan with the IMF. So we're back to "square one".
In theory, legal tender means money that is legally recognized and mandatory for use. But bitcoin is no longer a mandatory currency but an optional currency, meaning bitcoin is no longer legal tender in El Salvador.
We are back to square one in making bitcoin a legal tender.
I think what's holding back other countries from adopting Bitcoin as legal tender is its volatile (unstable) nature. They're afraid BTC will go down all of a sudden, leaving many users "rekt" in the process. For now, countries will add BTC to their reserves as a sort of "digital Gold". It will take a long time (if any) for Bitcoin to become legal tender. Why the hurry, though? People can use Bitcoin freely in countries with pro-crypto regulations, regardless of its "legal tender" status. The US is one of those countries that hasn't officially declared Bitcoin as legal tender, but many people are allowed to use it as a medium of exchange. Once the "volatility problem" is solved, BTC's use as a digital currency will skyrocket. We'll see what happens in the long run.
I think the volatility is just a secondary reason, the main reason is that they cannot control it and that will make it difficult for them to manage the people as well as regulate the national economy.
So I think we should forget about the idea that bitcoin will become a legal tender someday. Instead, expecting it to become and be used as an alternative payment method sounds more feasible and realistic.