IT Airbus
Ideally there would be a government-funded "IT Airbus" corporation similar to he highly succesful Airbus airplane company.
But even if that does not immediately materialize, there are plenty of starting points to wean yourself off the monopoly behemoths.
In almost all sectors there exist little-heard-of alternatives such as Fujitsu SPARC, MaxDB, CompCert, SoftMaker or BS2000.
Here is a list:
https://di-fg.de/IT_Airbus.html