Change the ticket structure so that you make money from the passengers that are travelling. Rather than relying on business and 5 day a week commuter traffic that is in free fall.
Unfortunately, this does not follow the rules of Economics. Firstly, the pre-Covid costs of running the railway v ticket income requied a subsidy from the Government to make it balance. If income from ticket sales fall, does the Government have the capacity to make up the shortfall - probably not.
Secondly. if you change the ticket structure, then the inference is that you will increase ticket prices which could reduce demand and ticket income.*
The upshot of both of these is that economies would have to be made, be that line closures, staff efficiences (a euphanism for just about anything) or other reductions.
(I accept that the strike is not the only factor behind reduced passenger numbers; Covid and staff shortages affecting performance have also had an impact. However, the end result is the same.)
* A braver option is to permanently reduce fares in the hope of attracting more custom and hence more ticket income, but that does require some careful analysis and a brave Government, and also that the raiways have the capacity to deliver, whether peak or leisure /off-peak flows.