The solution for Taiwan is obvious. Nuclearization.
The only way for a country of that size to resist a superpower is to ensure that that superpower loses their capital if they dare bite.
The only way for a country of that size to resist a superpower is to ensure that that superpower loses their capital if they dare bite.
That's not MAD. Also I'm not sure if it's even plausible that Taiwan could successfully target Beijing even if it had nukes. Would their system be able to survive a first strike? Would it be able to penetrate hundreds of miles of Chinese air defenses or defeat an ABM system? IIRC, ABM systems are far easier to build if you're willing to put nukes on the interceptors.
From my armchair, Taiwan's best bet is to create an Israeli-style reserve army that can mobilize most of the population to fight a short, intense war.
do they need to target beijing? Targetting guanzhou would already wipe out any gains from capturing taiwan.
That doesn't address the lack of MAD nor any vulnerability to a first strike.
It's worth noting that China isn't just "a larger power," it has a particular fixation on Taiwan. It may not be deterred as easily as you think. IIRC, Taiwan acquiring nuclear weapons is one of their stated red lines that would trigger a war.
If Taiwan managed to nuke a Chinese city when it's invaded, it would probably just make the Chinese madder.
P.S. Their military might not even be willing to invade if Taiwan is going to be lobbing nukes left and right, and possibly right into the invading force. Look at how China had to redrawn from their skirmish with India after they lose a few people to weather - and simply because the troops wanted to head home for Chinese New Year.
Cruise missile flying 100m off the ground.
For practical purposes, cruise missiles are the real wunderwaffe which is impossible to stop, not ballistic missiles.