I feel like your point that Finland and Sweden needing to join in secret would have more weight to it if it wasn’t for the fact that it would be suicide for Russia to open a second front on Finland and Sweden. They don’t have the manpower or resources to open a second front against two more countries let alone ones that have superior military equipment to Russia. I mean Sweden has a western armed air force that could ripe Russia’s apart. The only thing Russia can do is shake their fists at them joining NATO because quite frankly at this point they could probably beat Russia on their own without actually joining NATO. It’s just that even though they probably would win it still would be destructive and bloody so it would better to join as a deterrent
Finland and Sweden are small in terms of population, but they are wealthy and advanced. Sweden and Finland combined almost have the same GDP as Russia. Russia is a backwater economically, having the same GDP as Brazil.
This war is exposing what a paper tiger Russia is.