I’d do Lalashan in Taoyuan. Close enough to Taipei for shopping and socializing but love the scenery. There was a hotel there we used to stay at —called the Conjugal Love Farm.
lalashan taiwan - Google Search
My vacation in Taiwan - Travel / Taiwan Travel - Forumosa
I have extended family in Taiwan and may consider doing the same at some point but only after retiring in 10 or 15 years (mid 40s and can do it anytime after 55 with Canadian and Europe civil service pensions and lump sum benefits). However, I will already have two properties by retirement (UK now and one in South of France for wife in next decade after I inherit). It would be number 3.
In Taiwan, I would want cheap and rural.