Self-learning via books. I've bought a bunch. Am currently going through Susskind's Theoretical Minimum Classical Mechanics [1], also looking through No Nonsense Classical Mechanics [2].

AI chatbots sometimes come to rescue when I am stuck. Not with mathematics though.

[1] https://www.amazon.com/Classical-Mechanics-Theoretical-Georg...

[2] https://www.amazon.com/No-Nonsense-Classical-Mechanics-Stude...