For Bitcoin to be adopted as a legal tender, off course it must go through certain processes, but these processes are not ambiguous to say the least. Countries like El Salvador and not so recently The Central African Republic are Trail Blazers in the aforementioned.
Bitcoin legal tender boosted Bitcoin market in El Salvador in 2021 but I don't think it will be a main contributor for Bitcoin adoption in future. Considering that in the USA, people can use bitcoins for many things even it has yet been legal tender there. The same with Bitcoin adoption and usage in other countries globally, I see Legal Tender is not mandatory for Bitcoin adoption growth in the future.
The list of Bitcoin Legal Tender nations.
https://coinmarketcap.com/legal-tender-countries/