The US already imposed basically all the sanctions it can without just straight up trying to fuck over the Russian people as much as possible (the Russian people still got pretty fucked by sanctions already). Because of previous sanctions the Russian economy has a high degree of independence now and impact of sanctions is pretty limited.
I believe Russia had signed a deal with China to trade in their own currencies, as Russia attempts to fully de-dollarize their economy and trade. This was done since 2015 when the initial sanctions where applied.
I don't know if you're trying to be sarcastic, but I'll assume good faith - the goal of US sanctions is to destroy the Russian economy as much as possible to weaken Russia. Russian citizens coming to the US is good for the goal of weakening the Russian economy.
Russian spooks would find a way into the US no matter what.
If I visit Iran, I can not go to USA.
I think US should apply the same rules, and cleanse themselves from all Russian influence. All Russian developers, tech, companies...
If you go to Iran, you certainly can go to the USA after. You just need to ask for a new passport, and the US will never know what happened.
These sanctions aren't about influence. It's really just about trying to weaken Russian economically. The US government seems to think that Russian and Chinese influence is not that big of a problem, and they are probably right.