It wasn't just those three that left though.
Yeah, Kamala went away because she found out about her own averted death. Miles left because he felt guilty over the deal, and Amadeus because of Agents of Atlas (notably, Kamala quit the former Protectors team for that exact same reason, she couldn't be in two places at once). But there was also Wasp, who took a sabbatical because of her bipolar diagnosis, Ironheart, who was annoyed at Viv for trying to kiss her, and Nova, who went off into space to get his helmet back, not realising that it was on Earth (and Peter Parker knew - why the hell didn't he get Miles to pass the message on!?!). Viv and Snowguard were the only ones left from the volume 2 team.