If Russia withdrew their troops, there would be peace immediately

That's technically true. However, Russia uses military force in its sphere of influence for a reason, not solely because Putin bad (which he is, I'm a commie and Putin is fascist-adjacent at best).

Russia, like all big capitalist countries, wants to secure a sphere of influence in which it can do easy trade, influence the politics, and generally have support from these countries. The US does this for example with western Europe through NATO, and with less diplomatic methods by supporting coups and invading other countries. China does this through economic trade and through massive investment projects. Russia is in a weak position internationally, barely recovered economically from the dismantling of the USSR, and it's surrounded by former soviet republics very much in a similar plane (barely economically recovered from the 90s crisis as a consequence of the dismantling of the USSR).

These post-soviet republics, such as Ukraine or Georgia, adopted capitalism (as Russia did) in a very quick and disorderly fashion, and the resulting oligarchs and capitalist owners ended up fumbled in a mix of pro-russian and pro-european/US positions.

The EU and the USA both exert pressure on these countries to try and bring them to their side. Being economically and politically stronger, they can use trade, diplomacy, intelligence and economic means to alienate these countries front the Russian sphere of influence. Russia, in a more precarious and weaker economic and political position, simply doesn't have the means to maintain the diplomatic, economic and intelligence means to maintain these countries aligned to itself.

The war in Ukraine, much as the interference in Georgian and Romanian elections by the EU, mustn't be understood as a struggle between freedom and oppression. It's sadly just a struggle between two capitalist empires, namely Russia and US/EU, fighting for the control of smaller countries that they want aligned to themselves.

Once Russia doesn't have the means to economically, diplomatically and through intelligence, to influence its former sphere of influence into staying by its side, the only option left is the military route. The US and the EU know this, and they keep trying to mess with Russia's sphere of influence for gains to their empires. The reality is that there is no good side and no bad side: it's just struggle between opposing empires.

So yes, technically if Russia withdrew its troops, there would be peace. But this peace would mean that firstly the surrounding regions around Russia, and Russia itself, would become colonies and vassal states of the western world. It wouldn't mean "freedom" for Ukraine, as we can see by the exploitative contract for the minerals of Ukraine that the US offers. If you think the EU will offer something substantially less exploitative towards Ukrainians, you're wrong.

Ukraine, sad as it is, as long as it remains a state between empires, will suffer the effects of both. And only socialism in Europe and Russia can offer a meaningful response to this.

There wasn’t peace before Russia invaded. The far-right US puppet regime was slaughtering ethnic Russians in the east, and allowing NATO to move in troop and missile deployments to the Russian border.

Why would Ukraine behave differently after a Russian withdrawal, when they were escalating for 8 years prior to the invasion?