Taiwan in March will likely be damp and relatively cool - 15c or so - you’ll want to wrap up.
It’s not super-formal, so you won’t need suits or anything really fancy. Separates will work in the office and outside, and will help with your packing. I’d take layers that can build into multiple outfits or work together on cooler days, so a packing list might be:
soft trousers / leggings x 1 (for travel and downtime)
trousers x 1
office dress x 1
thermal undershirt x 1
shirt x 1
Lightweight jumper x 1
Blazer x 1
lightweight puffer / gilet x 1
Flat comfy shoes x 1 (loafers?)
Plain trainers x 1 (lots of walking trails, hiking and outdoorsy stuff, plus good for travelling)
Big scarf x 1 (for plane and extra layer as needed)
Pack all this in a fairly neutral or complementary colour palette and you can combine them together to make dozens of different outfits.
When I travel internationally for work, my aim is always to be able to wear each item with 3 others in my case, so everything goes together. You can always add in accessories like scarfs, necklaces, small bags etc if that’s your thing too.
Have a great time! Taiwan is ace, get your host to take you to visit the night markets!