Xsmisee

Toxic BL recommendations? Ideally if both leads are kinda toxic! Just finished one that was so good but too short

I'm going insane trying to remember what the title is:

In the first chapter it was a guy who was originally from a Hi-Tech future fighting aliens? He then blows up everything with himself since all his comrades died and then found himself reincarnated into a fantasy world as like a 15/16 yo lord (blond haired). Then typical fantasy male lead stuff happens.

What I liked was that it was not setup for him to take over the country or something like that - it was getting sort of interesting where he meets like a Prince / heir to throne on the way while negotiating to get water from a lake from where I left off.