What is the ruling on installments for household appliances for government sector employees in these stages, and how can Sharia violations be avoided in it?

All praise is due to Allah. As long as the company owns the goods before selling them, and sells them at a fixed price upon concluding the contract, and does not stipulate prohibited conditions such as late payment penalties, then there is no harm in investing in it and benefiting from its profits. The increase in profit due to installment payments is also permissible, because time has a share of the price, and selling on a cash basis is not the same as selling on a deferred basis.