The sanctions are nothing to them.
They've already made their own rule for the countries that they're dealing with and it's in favor of them. So all of the people that boycotts them or not, they won't care.
You decide if all casinos based on Russia will be boycotted by you or you don't do anything as that doesn't concern you and they're just businesses that are residing there and as well as affected by the war.
I think Putin was prepared for the fact that Russia would be subject to sanctions and he certainly secured himself for at least many months. Even if these sanctions make his life difficult in some way, they will surely not change anything in short time. Putin knows that all countries that buy gas and oil from him will not find new sources even within a few months, so nothing will change for now. However, in the long run, Russia will certainly lose a lot, because what is happening in Ukraine is huge costs for them.
Maybe or maybe not.
Because he thought that this war would only take a few days or weeks and now it's being prolonged because both of them doesn't want to give what each of them want.
The countries that are buying gas and oil from them could find another country to buy but it wouldn't be easier if it's coming from Russia just as before.