"Negative results" in the sense of replication failures and trial pre-registration are incredibly important. Lean is in some senses a mathematics response to the maths replication problem -- fields are so specialised, and proof checking so onerous, that many errors will go uncorrected.
Arguably mathematics should have pre-registration, so you can see who has tried what before, rather than just by knowing everyone in your field. As LLMs progress, we might get pre-registration of LLM-aided research. "We plan to spend $10K on Fable tokens to look at conjecture X is algebraic co-homology."