I don't think this can escalate more from Russia's side. They already invaded neighbouring countries, and not only are they keeping their war machine running but they are also threatening more countries while shifting their economy to a war economy.

At this point, either Russia voluntarily stops it's invasion and leaves Ukraine or inevitably NATO will have to step in. Whether it's before or after Russia invaded a NATO member is still to be determined.

As Russia is all-in, the only option on the table that prevents NATO from stepping in is to support Ukraine and supply them with the necessary and sufficient equipment to drive out Russia. If there's no political consensus to deliver what's needed, it's only a matter of time before Europe's armies are deployed.