That's...not right at all.
He has combat capablities (he has the dagger) hes just not a combat class. He can't get to the other floors at all because he appeared on the 99th floor and can't warp anywhere after attuning to the waystone (minotaur chapter).
Outside of the seed shop he uses theo to buy what he needs and what theo wants and usually gets something good in return.
I thought Theo just bought those things on his own, which now I actually think about it is stupid and I have no idea why I thought it.
Though he has the dagger does he know how to use it effectively in combat? This story mostly focuses on farming rather than combat so it's hard to gauge but it does raise questions on weather combat in the tower is based on how good at fighting you are or how good at leveling and using abilities you are.
How is transportation in the tower done? is there no way to lower floors without the gates?
I was also tired when making the original post and mostly just throwing out questions so if I missed some logic or answers I blame my sleep deprived brain. I'm also tired now so I'll be going to bed soon so if any one wants to lambast me for my failings at reading the story I'll get back to you one day.