Finland is opening the door to the idea of joining NATO and their concerns are not unfound. Russia may or may not take Ukraine, then 10 years down the line the next leader after Putin decides to put additional pressure on European countries that might be geopolitically opposed to them. Too many people are not thinking beyond the scope of one or two years, as if they might have forgotten the more recent wars that've taken years before coming to a conclusion. Russia's ambitions may not stop with Ukraine.
On the other hand, China is formulating a plan to invade Taiwan, seeing how the Russian war with Ukraine went (little to no international response). It will be amusing to see the shock on world leaders' faces when this happens. They seem to be ignoring China as a global threat.
Finland has every right to be worried. They might as well hurry up and join while Russia is preoccupied with Ukraine. I guess that's Ukraine's biggest mistake, they haven't coordinated with the other neighbors (except Belarus of course). Maybe if several neighbors were threatening to join NATO at the same time, Russian response would be different. They'd probably still invade Ukraine first though (it's the bigger prize) before doing Finland.
As for China, it's really only a matter of time. I just hope it'll be less bloody for the Taiwanese. Maybe also the response from the US would be different, an annexed Taiwan would endanger the chain of naval bases America has set up in the Pacific and by extension, the West Coast. These are the same bases the Japanese tried to dismantle to open up an attack on the American mainland.