Recently experienced these coffee shops/bakeries mostly in Southern Taiwan. Frequently open 24 hours, have plenty of seating both tables and comfortable chairs, free wifi. Really good bakery food.
Edit: No donuts at Donutes.
Some in Taipei area have not tried yet.
No. 1號, Jingan Road, Zhonghe
No. 110, Fuxing Road, Taoyuan District, Taoyuan
A few locations I Iike in the south open 24 hours.
No. 117, Zhongshan Rd, West Central District, Tainan
No. 206號, Yisin 2nd Rd, Qianzhen District, Kaohsiung
No. 643, Xinmin Road, West District, Chiayi, https://maps.app.goo.gl/FfLMMQVFgx6ALWWx7