In Tetris Effect: Connected, unlocking new avatar icons for use in the multiplayer Connected mode is an engaging process that revolves around gameplay progression and achieving specific milestones. Here are the key aspects to understand about how avatars are unlocked:

1. Experience Points (XP) System: The primary mechanism for unlocking avatars is through earning experience points (XP). You gain XP by playing various game modes, including both single-player Effect Modes and multiplayer matches. Engaging in gameplay across these modes is essential to level up and access different avatars.

2. Single-Player and Multiplayer Engagement:
– Many avatars can be unlocked by achieving ranks and fulfilling challenges within single-player modes. However, it’s important to note that while these single-player achievements provide numerous unlocks, they do not yield the full range of available avatars.
– To unlock the complete total of over 100 avatars, participation in multiplayer mode is necessary. The multiplayer experience not only contributes to your overall XP but also includes specific avatars exclusive to Connected mode.

3. Unlocking Guardian Avatars: In the multiplayer environment, you unlock special avatars known as Guardian Avatars. Winning matches and participating actively in multiplayer sessions is crucial for accumulating XP, thereby allowing access to these unique avatars.

4. Special Event Avatars: Participating in weekend events, such as the Weekly Ritual Event in single-player or the Full Moon event in multiplayer, offers players the opportunity to earn exclusive event avatars. To successfully unlock these avatars, players must contribute to reaching 100% progress in the event tasks by the end of the event timeframe.

5. Total Avatar Count: The game starts you off with a default avatar that does not contribute to your unlocked avatar tally. You must unlock new avatars independently, with the milestone of earning at least 100 unique avatars (excluding the default) being necessary to trigger certain in-game trophies and rewards.

In summary, to effectively unlock new avatar icons for multiplayer Connected mode in Tetris Effect: Connected, players need to engage in a balanced mix of gameplay across both single-player and multiplayer modes, participate in special events, and focus on achieving a total of at least 100 earned avatars. This comprehensive process encourages consistent gameplay and achievement of in-game objectives rather than relying on a single method for unlocking content.