I personally do not think that sanctions are useless, they still have benefits, if the people support the war, then they must live in poverty and suffer.
This is an axiom.
USA & Europe representatives were saying that sanctions would trigger Russian citizens to do something and change Putin or his decision and stop the war but in reality, sanctions can't change a thing inside Russia. What do you think, there are millionaires and billionaires in Russia but none of them have ever established a real political party and power against Putin. There is a question, why? Because Russia is a corrupt country, they make money because of Putin and his regime. Sanctions can't really stop this process, Russia is being sanctioned for months but the war still continues. What do they have to lose right now? Sanctions won't be abolished if Russia stops the war.
Si vis pacem, para bellum - If you want peace, prepare for war.
This is what life teaches us.
If sanctions are useless, then the absence of sanctions is even more useless.
If russia completely cuts off the export of oil and gas and prohibits the import of high-tech products to russia, as well as the technologies themselves, then there will be a very tangible benefit, russia finances the war at the expense of oil and gas.
You are right, they are not completely useless, just not effective.
France, Germany, and Hungary provide $1B/day to Russia to finance this ethnic genocide.
The only thing that would work IMHO is a total trade embargo on Russia, confiscation of assets of all Russian citizens,
and their deportation back to Russia.
The breakup of diplomatic ties with Russia by all civilized countries might be effective.