The amount of Mycelium you receive from a mission depends on its final star rating. A 1-star result provides the baseline amount (equal to the Totem’s conversion). Higher ratings (2-star and 3-star) provide increasingly more Mycelium, reaching the mission’s maximum potential amount at 3-stars.
Note: If you sell or transfer a character collectible that is part of the active squad before the mission completes, it negatively impacts that specific mission. This could manifest as a reduced chance of success or an increased mission duration, potentially leading to failure or lower rewards than initially anticipated.