The US think tank Institute for the Study of War (ISW) wrote an article about a possible Russian attack on Estonia. This is a hypothetical scenario, not a prediction.
Russia could test NATO unity with a small operation. They could use drones and small military units. Russia does not plan a major war but wants to confuse NATO.
Russia's goal would be to create a difficult situation for NATO. They could try to damage NATO's trust and create a political crisis. For example, they could force NATO to divert resources to Estonia instead of Ukraine.
Russia could use propaganda and information warfare. They could claim that Estonia is oppressing the Russian population. They could also use drones for small-scale attacks.
Russia could launch a limited attack on Narva. They could occupy some buildings and declare the "Narva People's Republic". NATO and Estonia would then have to respond.
NATO's biggest problem would be the implementation of Article 5. Some allies might fear escalation to war. Russian information warfare would aim to exploit this fear.
Drones would be important in Russia's plan. They could use large and small drones to attack Estonian forces. NATO might struggle to stop these drones.
The conclusion is that NATO needs to be stronger and ready to respond quickly. NATO needs better drone defense systems and a faster decision-making process.