I have tried various clients on my Graphene phone and am currently using Sipnetic. I have it excluded from VPN through split tunneling, but I still have periods

I have tried various clients on my Graphene phone and am currently using Sipnetic. I have it excluded from VPN through split tunneling, but I still have periods when number just doesn't register. I know there are various settings that can be tried which I have done, but this configuration is a constant source of frustration for many. This is why I recommend jmp.chat with Cheogram client for those looking for a solution that just works. What client or configuration have you found to give you consistent connection with voip.ms?