An invasion would have to happen in October or April because of sea conditions. Should be an interesting month.
They pretend to catch fish and then some of them claim that they have engine problem, using it as an excuse to land on one of small Taiwanese islands. They are followed by other trawlers, ostensibly to help them. If Taiwanese military tries to stop them, Chinese will pick a fight. The ensuing violence would be broadcast live on Chinese media, inciting population into a frenzy.
Then "Patriotic" Chinese navy and air force will be mobilized to "rescue" them. Their media will be filled with non-stop broadcast of people wishing for the safe return of poor "fishermen" and outpouring of support for "brave" Chinese military.
It would be interesting if this will end up as a Chinese rout. Xi will risk his ouster if he does nothing. Probably, his only option is escalation.