Sigh, it is super easy to deal with nuclear waste, you find stable bedrock, drill a hole into it, put the wast into the hole, backfill with clay.
Done.
There is zero need to build momuments to warn future civilizations, as long as it is deep enough, we can expect their technical development level to be on our own level before they can dig it up.
I am a Swede, we have stable bedrock, a stable political system, we have the skills to build a facility like this, we have a shitload of space for it. We should invest in large storage facilities for nuclear waste, we can make enough to fill the global demand for nuclear waste storage, and we could make a plenty of money doing so.
Also, it can be quite cold in Sweden, we could build the sites with heat exchange pipes surrounding them giving us decades of boosted geothermal power.
If I were a billionaire, I would focus on building nuclear waste sites for the benefit of mankind.

