Ah, understood. I’m unaware of any clients for Linux that would do what you’re asking for. You could try using Anbox to run android apps and use the android solutions I’ve recommended in my last comment through that, but that’s all I’ve got. Good luck!
Getting another number helps a lot in my opinion. If you’re getting another sim in the same phone, I suppose it would be possible for whatever cell carrier is providing the service to be able to link your two sim cards to your identity. However, for other companies, I don’t know of a way they could gather that your second sim phone number is linked to your first one. For instance, if you created two Discord accounts with your two phone numbers, you could theoretically be two completely different users that won’t be linked together. I would personally go for a second number.