sooo title says it all throw anything please I'm desperate atm all I know is https://www.novelupdates.com/series/black-summoner/
Never read Black Summoner before but the MC in Stop, Friendly Fire! Does not know the meaning of getting tired from battle.
Dragon's Bloodline - mc is definitely battle junkie but the novel is gender bender so if that is not your cup of tea be aware.
The translation is terrible but; The Sage Who Transended Samsara https://www.novelupdates.com/series/the-sage-who-transcended-samsara/
The only story that I'm reading at the moment that I would consider to have a battle junkie mc is azarinth healer(on RR)
Youjo Senki - It's a gender bender, psychotic flying loli, self-proclaimed pacifist but a ruthless and efficient soldier who doesn't hesitate. (I personally recommend reading the manga cause I don't freaking know where to get the complete translated novel...and also the manga has amazing art, specially compared to the anime...but how the anime portrayed being X is by far the coolest, but that's not important to the story, I'm just talking about art and visuals here. lol)
It's a really nice JP series, you need to be cautious that it's 1)Gender bender 2)Yuri (1 sex scene not shown) 3)Futanari (2 sex scenes where it says there is penetration and release).
The Primal Hunter on Royal Road is what you are searching for. No romance, few side characters , a cool power system and a huge universe to explore + a mc who lives for the thrill of battle.