Ableton and FL Studio are both serious DAWs. The choice is not about which one is professional. It is about which workflow helps you finish more tracks.
Choose Ableton if you care about electronic performance, clip launching, audio warping, racks and turning loops into arrangements quickly. Choose FL Studio if you want fast drum programming, an excellent piano roll, pattern-based sketching and a beatmaking-first workflow.
Session View is a sketchpad and Arrangement View is the song. It is brilliant for testing sections, warping audio, building racks and performing ideas live.
The Channel Rack and Piano Roll are the writing engine, and the Playlist becomes the arrangement. It is fast, visual and excellent for drums and melodies.
Both DAWs have strong stock tools. Learn EQ, compression, saturation, delay, reverb and utility inside the DAW before chasing third-party plugins.
Ableton users must leave loop mode. FL users must turn patterns into full Playlist arrangements. In both cases, finishing is a habit.
For EDM performance and audio manipulation, Ableton has the edge. For fast beatmaking and piano roll composition, FL Studio has the edge. For a beginner, either is excellent if you follow one complete track workflow and avoid switching too early.