Other nations would be wise to oppose their admittance. There is no upside for them, only risk.
This is short term thinking.
What if Finland does not join NATO and Russia invades? What if Russia succeeds? In the next decade it will invade Sweden that’s also not in NATO. At the end of this process, Russia will still border NATO in the North. Only this time Russia will be a much bigger and a more powerful state. What’s the upside for NATO in that?