Well, take a look at the guide I have linked to, because it has all the practical information you need.
So, it looks like you would take the Vdlp from Sevilla to Mérida, and then walk the Mozárabe ”backwards” to Almería. I would recommend a GPS, but this is entirely do-able. I assume you have found plenty of information on the Via de la Plata from Sevilla to Mérida. Gronze lists about 9 days for Sevilla to Mérida.https://www.gronze.com/via-plata I walked from Almería to Mérida in 21 days, you might want to add a few if you don’t like long stages, but the guide gives plenty of options for shorter stages.
That would be a really great walk, IMO!
Buen camino, Laurie