I would advise checking the decay curves for nuclear waste and checking what levels of radiation cause harm. The tldr is that waste that decays slowly is doing

I would advise checking the decay curves for nuclear waste and checking what levels of radiation cause harm. The tldr is that waste that decays slowly is doing so because its releasing less radiation. There's no radioactive stuff that we'd need to worry about on the million year timescale. The 10000 year timescale is the most where human health due to radioactivity might be a concern. And on those timescales your waste at the bottom of the ocean or 100ft below ground is almost certainly going to be still there and unaffected unless we or our successors decide otherwise. Heck I'd say worrying about anything more than the 500 year timescale is absurd as I'd be very surprised if humans were still around in human form by then. We'll either have been genetically engineered, wiped out by those who have, wiped out by rogue AI or something else or been "uploaded" in some fashion.