I tend to think of Dagobah as akin to Dragon Ball’s Hyperbolic Time Chamber/Room of Spirit & Time. One year inside the chamber takes up only one day outside of it. Dagobah time is elongated, which would account for the extended time Luke spent training/Yoda’s age catching up to him a bit more.
That’s just a “head canon” for me.
That’s a cool idea, though I doubt Lucas thought of it that way and probably just ignored the specific time length details for the overall “feel” of the training montage.
Thumbs up to you for spelling head canon right and not the silly headcannon, which IS something in Dragonball, hahaha.