If you are not some well-known Soros shill, in the worst case you will pay some fine for "uncoordinated rally" if any. You again know about Russia only bullshit that Russia's worst enemies told you. There are no any punishment for protesting against the war. Even the loudest protestor, TV channel editor Ovsiannikova is back in Russia, free and well. There is punishment for spreading lies (like that stupidest Bucha fake) with intention to discredit Russian Armed Forces and you have to try hard to attract an state attention.

With Soros shills anything could be used to detain and neutralize them - from manufactured financial charges (like was done with Navalny) to the made up convictions in all that stupid "extremism", "therrorism", "discreditation of armed forces" or whatever. If you are regular citizen not connected with Western financial circles, there is nothing serious could happen with you.

Separate case is so called "ethnic hatred". Designed specifically by jews and to protect jews this law could be applied to regular citizens with up to few years in jail if you was too active in public. It used mostly in cases of "hatred" against Jews and Caucasus tribes. Only once it was used for "hatred" towards Russians to detain one Soros shill who posed as "journalist". And you could be convicted in "hatred" towards Ukrainians too, as one jewish faggot that worked on one of mainstream TV channels nearly had. Being Jew saved him from criminal prosecution.

Meaning of the "law" in Russia is different from one the West used to. You could don't give a fuck to some stupid law and nobody will care. And even stupidiest and unconnected law could be used to neutralize state enemy that have serious resources from outside to evade conviction directly connected with his activity.

Law is not some dogmatic or absolute thing in Russia. At all. Good or bad, but unless you understand that, you can't began to understand how things here work and will always do a wrong assumptions and conclusions about Russia and Russians.

What happens to a Americanr in the US who will demand change of political system in his country, say, removing POTUS position or insisting on direct voting, not that stupid "voters" scam?

What happens to a European in EU for uncovering lies about Holocaust?

What happens to a Westerner in West for demanding return of psychological ilness definitions for faggots, trans and other evolution garbage?

For current state of affairs, looks like you will be more free to express your views in Russia, than on the West.