You are getting there. The Hydrogen Balmer lines in Denebola in particular are nice and clear.
There’s no Methane in Sirius but the Hydrogen Balmer lines are visible. The H2O telluric line marked should be at an absorption line. The most obvious telluric line is the broad O2 band at ~7620, off the edge of your plot but very clear in the image you posted on “Cloudy Nights” and “StargazersLounge” forums. The other humps and bumps are from the camera’s 3 colour filters. (Monochrome cameras are better in this respect for spectroscopy)