First of all I don't think you are an awful person, on the contrary if you are concerned about other people mourning you while considering your own death I'd say you are a very empathetic person. But I also know what you mean cos I have those same thougths too and often.
The desire to just disappear completely, erase yourself from history and people's minds, the Great P O O F, that just can never be fulfilled. Because it can't. And like you say it feels violating, like chained to the world even in memory, prying eyes at your ghost, society and its bullshit dynamics following you where they shouldn't, uninvited. When I leave I don't want to be thinking of a part of me that stays. I want to leave whole.
Countless times.
I've fantasized spending a day going door to door of everyone I've known with the lil men in black flash memory eraser thingy, then just dying in peace by nightfall.
I've thought of leaving letters saying "Bye loved ones, I've joined a circus to pursue my hola hoopin dreams. Please (if at all) think of me as somewhere out there living my best life" then crawl into a well.
I've envied those who wouldn't be missed, without ties or loved ones. Felt like an absolute moron just thinking that.
I've purposefully alienated friends, slowly isolated and ruined friendships in the process of planning my death in hopes they'd forget about me and not miss me once I was gone.
And other dumb yet equally relevant acts of desperation.
I know that a part of it is empathy. Because we are suffering people and wouldn't wish anyone even a fraction of what we go through. Be it grief, regret, loss or the pure desolation we carry. We know. It's-not-great. We wouldn't like to pass that pain on to those we love or ever loved us. We just want it to end. Most of us already feel angry at ourselves for our sense of burden. We feel angrier when we realise death wont alleviate it, it may even enhance it.
And another part is more insidious. More tied to our self deprecation and desire for total anihilation. We can choose to end our lives, but we can't choose over people remembering us, so the desire is left incomplete. We can't reduce ourselves to nothing. This is also infuriating, but its source is meaner.
So yeah, it feels like a prison. Either live in pain as a burden to those around you, or die, become a ghost of gossip and fuck them all up with grief. A shitty human condition to be in.
However... I'm honestly both very angry at it and very grateful for it as it has kept me alive so far. It's like a weird Stockholm syndrome with life itself. The world's most unconfortable raft in an ocean storm. Fuck you I see you tomorrow kind of thing. I don't get along with it. I don't like it. I'd like it gone. If this whole thing had a name It'd be an insult. But it has its bright sides. In our mutual hate we are still kicking, and enjoying the few things that allows us.
I don't have a solution for this impossibility of total oblivion, but I'm starting and trying to not care for it. Still hate it, but I reap its harvest. I only hope you, I, us, everyone can do that or reconcile it in some manner that suits us individually and not succumb to the meanests parts of us.
Hope that made Some sense. I'm sorry if I rambled (I did) but yes this topic in particular feels important to me. You can pm any time. Lots of hugs. Take care <333