After approving Finland's accession to NATO, fears increase about its impact on security and stability on the borders with Russia, especially since Moscow has always refused to expand the alliance to approach its borders and lands.
By joining NATO, Finland becomes more secure under the security umbrella of NATO. And NATO becomes even stronger by accepting Finland. Russia may concern about this development, but there is no possibility of a direct threat to its borders. Because no one dares to military attack a nuclear superpower such as Russia. The same is true for Russia too, even though it threatens some small NATO states rhetorically, but in reality, Moskow does not want to direct conflict with NATO because of the severe consequences that Russia has no capacity to bear it.
Finland's accession to NATO has further deteriorated political relations between the two neighbouring countries. However, these relations are now practically non-existent anyway and the level of economic cooperation is rapidly declining (recent Finnish data on imports and exports with the Russian Federation). The Russian Federation's border with NATO has lengthened considerably, which necessitates large investments in military infrastructure by Russia and provides a good excuse for those in power to expand the army. Regarding the security situation for Finland as a NATO member. It has certainly not worsened or improved. It will be very tense in the near future, as it has been since the beginning of the Ukrainian conflict.
All the states that join NATO do so because they want to, not because NATO is pursuing a policy of expansion. The initiative belongs to the states. If they offered Russia something better than NATO, many Eastern European countries would turn to it. An increase in tensions with Russia is not supposed to happen, but it seems that the leaders in the Kremlin react negatively when its neighboring countries choose to be friends with the US. If, however, the tension between Putin and the West increases, this will lead to increased military spending by Russia and increased spending on "gifts" to friendly countries (selling hydrocarbons, wheat, timber and minerals below market prices, loans, etc.). Russia could have lived for decades by selling its huge resources for a lot of money to the West, but its leaders chose to sell them below cost to other countries. In 4-5 years, when they draw the line, these leaders will realize the scale of the disaster. Conclusion: for its own sake, Russia should calm down.