Broadband infrared spectroscopy and 𝑎𝑏 𝑖𝑛𝑖𝑡𝑖𝑜 calculations for RbTi3Bi5 and CsTi3Bi5 offer novel insights into kagome metal physics at low band filling. The study uncovers an intricate interplay between Bi 𝑝 states, forming a tilted Dirac crossing, enhanced electronic correlations from Ti flat bands near the Fermi level, and anomalies in electron-phonon coupling that can be paralleled to the onset of nematicity.