As per your own assertion , we have a difficult situation till 2025
So what else is a solution
There's no solution. It's just a lesson to all that if you screw up, you will suffer for it later. What goes around comes around.
Second-hand jets are not a solution. Neither Taiwanese nor French Mirage 2000s, even if available, will require upgrades, which won't happen until after 2025 even if we sign up today.
Our only immediate solution is to upgrade whatever we have with better weapons, like getting a decent number of Derby ERs for the MKIs and LCAs within the year. And hope that the LCA project is not delayed any more than it already has.