Rapid manufacturing of optical waveguides in highly nonlinear lithium niobate paves the way for enhanced photonic integrated circuit (PIC) development applied in e.g. quantum photonics. Conventional fabrication of PICs requires usually multiple production steps while lacking rapid prototyping and reusability of substrates. Here, we present the fabrication of strip-loaded waveguides on 900 nm thin-film lithium niobate on insulator (LNOI) with a single-step production approach of two-photon polymerization (2PP) that addresses these shortcomings. We report propagation losses between 1.2 to 5.1 dB/cm for these waveguides and support the experimental work with simulations