Vietnam or Japan June 2026

I'm from Ireland and planning on travelling in May and June 2026.

I am visiting Malaysia first - then Taiwan - then Hong Kong. I'll enter Mainland China from Hong Kong.

I was originally going to move from China - to South Korea - to Japan - then home via either Canada or Singapore.

But to reduce costs I'm thinking now instead of South Korea and Japan (and Canada or Singapore), instead I'll go to Vietnam from China and spend 1 - 2 weeks in Vietnam then head home to Europe.

How does Vietnam compare to South Korea and Japan?

Should I do South Korea and Japan as part of this Asia trip, or should I instead do appx 2 weeks in Vietnam? I'd like to know the pros and cons of both.