"Governments" are not against Bitcoin.
Unfortunately, no, governments (almost all) are against bitcoin and if they could ban it, they would have done so already. Why should they give financial freedom to citizens?
Some governments are, some are very open to it and want to create an enabling environment for it.
More often than not, countries that are open to this have no other choice, because their financial and economic sectors are in very poor condition (El Salvador). For such countries, bitcoin is like a booster, allowing them to bypass other countries (anti-btc) in the economic race. In essence, they show loyalty to the bitcoin out of their own interests, and not out of the interests of citizens.
Also, those against it are not doing so because criminals are using it. Criminals are using their legal tenders way more but there's no campaign against it.
This is all a stupid story about criminals using bitcoin to demonize it in the eyes of ordinary people. Let them then ban cash if they talk about
criminal money.
how would it be if Government finds a way to regulate it and all or most countries adopts it as legal tender?.
Get rid of these illusions. It is easier for governments to issue their CBDC and impose it on citizens than to accept BTC as legal tender.
Any government will legitimize only the money that it can unconditionally control (emission, turnover, etc.). Bitcoin is not subject to any country in the world, therefore, no country in the world will allow it to be made legal tender. National currencies (as before) will be used, probably digital versions rather than bitcoin.
A small digression:
In any country, legal tender is only the local national currency, that is, even in Turkey, it is illegal to pay for goods and services in euros or dollars. And you are talking about bitcoin.