Very secure Mail or chat server with auto-delete messages (Like Signal)

We're looking for a email / chat server to host in a VPS that can offer messenger for a small group, where direct messages and or group messages can be configured to auto delete after some some time, like 5m, 10m, 1h, 1D, 3d, 1w .....

We want you to:

1.- Provide the Server software solution name and details

OR

2.- Also the posibility to install the software in VPS for us.

Thanks