You can stop being the organizer and remain part of the group.

Roles harden quietly. Whoever books the table and chases the replies starts to feel that the group runs on that labor, and stepping back begins to look like stepping out. Those two things come apart more easily than they seem to. Arranging things is a job you took on, not the reason people want you in the room.

Say plainly that you would like someone else to plan the next one, and then let it be imperfect. Come anyway. Answer the message when it is someone else sending it.