So what do i do?
Put my 300k in short term government bonds to fight inflation and slowly invest it (monthly) over lets say 30 years?
You haven't covered your tax situation which is critical. You want to move at least a significant portion to a tax advantaged account so it can grow tax free. You'll only be able to move so much every year.
The remaining portion I would buy into stocks or bonds according to whatever plan I chose, but I would be sure to max out those contributions to tax advantaged accounts ever year.
There are additional things to think about if you have other things going on, like a kid who's going to apply for student aid.

