What I've done and yeah I know, it still sucks.
@starbreaker@mastodon.sdf.org
thanks for your suggestion, that is what I would do but unfortunately (or, luckily) I'm not an employee, I need it to sell stuff online and to share info with other contractors, so no one is going to pay me for a monthly plan, another mobile and so on =D
What I ended up doing is installing #shelter, downloading #whatsapp with #YalpStore, cloning it into shelter and removing it from my main system.
I am all too aware that it's not a full #VM, I'm just putting some wire net around it, not a full box, but it **shouldn't** be able to access my data.
It has its own contact book and gallery to refer to, and I can avoid giving it many permissions.
By using shelter I can also freeze it, so that I stop it from running on the background no matter what, which is good.
It still sucks, but I couldn't come out with something better.
I guess sooner or later I'll have to go with a second device though, it's mostly the phone bill that bugs me.
A shout for the nice people who helped me:
* shelter: https://git.angry.im/PeterCxy/Shelter
* yalp store: https://github.com/yeriomin/YalpStore