Retirement tax questions

Sorry, this was the full post:

 

I took out a COVID-related distribution out of each of my two 403(b) accounts. My usual biweekly contributions is being deducted from my paycheck (pre-tax). I intend on paying back the distribution that I took from my 403(b) accounts. However, I am being told that I am unable to contribute this as a pre-tax deduction from my payment, such as by increasing my monthly automatic contribution. This doesn’t seem to make sense to me that I would contribute after-tax money to recontribute to a pre-tax retirement account as that is a) counterintuitive to the concept of not paying taxes on the COVID-related distribution and b) I would then get taxed again on that recontributed post-tax money in retirement. Any advice?