Just seen your DC are 8 and 12.
We were still reading to our DC at these ages, although sometimes the DC read to us!
At 12, your eldest may not want this if they're not used to it, but definitely worth giving it a try if they're amenable.
What are your DC's interests? If we can get an idea, posters may be able to suggest books they will like.
Here are some brilliant books my DC - one girl and one boy - have both enjoyed from age 8+.
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the Frostheart trilogy
For slightly older kids, maybe 9 - 12
At 12 they're getting more into young adult fiction. Some of which I wouldn't want to read with my DC as we'd find any romance aspect cringy to read together!
But His Dark Materials, Harry Potter and Murder Most Unladylike are still very enjoyable at this age, and your older DC may well enjoy listening in to stories for their sibling too.
My 12.5 yo DD is really into the Hunger Games at the moment, she reads it herself though so I'm not sure about the cringy romance aspect!
12 is also a great age to get into sci fi.
My DS really enjoyed The Hitchikers Guide to the Galaxy at this age (as did I, many years ago).
Have fun discovering new worlds together!