How much has oil increased in price since Putin announced?
Brett Crude is probably one of the best arbiters for the value of Russian energy assets (ergo the oil and natural gas they sell to NATO countries). Being a petro-state if invading a neighbor causes their #1 export to double in price and NATO is funding the invasion with energy purchases things are going poorly for Putin?
In Dec (red arrow) Putin first started making serious overtures about attacking the Ukraine. The result is pretty obvious and eclipses the economic impact of sanctions. As for being isolated, Russia is not isolated from its largest new energy purchase China (who has a limitless appetite for oil/natural gas).
As for Russian oligarchs putting pressure on Vlad. These guys make money because Putin says they can. He holds all the cards and can quickly imprison and seize assets of anyone who dares complain (as he's done in the past).
Yes, the Ukraine is putting up a ferocious fight, one Putin didn't expect. His short game has hit a few hiccups. His long game looks to be solid (albeit immoral).