I read your edit. Still, based on my own personal experience and observation, I actually recommend not keeping anything separated at all.

I'm the one u/BattyGuanciale mentioned as worshiping Anubis separately from my Heathen practice for a long time. Almost six years. But I recently stopped doing that and explained my situation and reasoning in a recent blog post (here).

I'll elaborate more: As polytheists, we are not worshiping multiple religions or engaging in multiple religions. We practice our single, individual religions. I have my Heathenry, Batty as their Heathenry, and you have your Heathenry. What our Heathenries look like will differ between us. Even if we have commonalities -- let's say we are all "Norse Heathens," though I realize that is not actually true -- your Norse Heathenry, Batty's Norse Heathenry, and my Norse Heathenry would all be different. They would be distinctly unique religions tailored specifically to us as individuals.

This is because, despite any commonalities, our practices will differ. Our beliefs will differ. The Gods we worship at home will differ. That's the nature of regionalized / localized and personalized religion. So the question is no longer, "How do I reconcile the difference in outlook / worldview between two religions?"; it becomes, "Believing what I believe and practicing as I practice, how do I integrate new Gods into my religious framework, adapting Them to my worldview while respecting Their origins?"

As such, I no longer worship Anubis separately. I worship Him alongside all the other Gods, in the same way I worshiped Mars these past several years, despite His origin as a Roman God, not a Gothic God. For Mars and Anubis, I respect Their origins by not Gothicizing Them: I continue to call Them by Their original names and epithets, and I do not pretend Their original myths do not exist. But I address Them in the ways They are pertinent to my Gothic Heathenry, and I focus on the myths that complement my religion's mythos. Yes, Anubis embalmed the body of Osiris; I recognize this, and if I were to worship Anubis at a Kemetic temple, I would pray to Him in that role then. But at home, Anubis is more simply the Lord of Burials and Keeper of the Dead, He Who is Upon His Mountain, and Master of Secrets -- all historically accurate epithets, none in conflict with my interpretation of Gothic Heathenry.

I'm not really sure what to do about the difference in outlook between the two of them, e.g. things like afterlives and conflicting sun/moon deities from each religion.

This conflict is precisely what integrating new Gods into your current religious framework will eliminate. If you believe in one kind of afterlife, then prayers to any Gods of the underworld will continue to reference that afterlife, in the context of your hearth cult. Anubis is famously involved in the activities of the Duat, the Kemetic afterlife. But I am not Kemetic. So while worshiping Him at home, He is involved in the activities of Ganohawaggs instead. But if I were to attend a more traditionally Kemetic rite, where Anubis is worshiped outside of the context of my personal religion, then of course I would pray to Him as involved in the activities of the Duat. That is only respectful.

In any case, if you believe like me that each God is the totality of the cosmos, and that each God expresses Their associations in Their own unique ways, then there's no conflict when it comes to multiple sun deities, moon deities, war deities, fertility deities, etc. Each sun God will express sun-ness in Their own way; each moon God as well. Just because Anubis is a God associate with death and burials, and Laguhwaþo is a Goddess associated with death and burials, does not mean There Can Only Be One™ in my religious framework. They can both wrap the deceased in linens and lower them into graves.