CDG ORLY connection

It is a very inconvenient connection... The bus between the two airports takes about 1 hour (you're avoiding the worst traffic with your landing time), with waits up to 30 minutes, so I would allow no less than 4.5 hours: 1.5 to get out of CDG, 1.5 to travel, 1.5 at Orly.
Orly being small enough that if you arrive, say, only 45-60 minutes before a flight you'll still make it. And if you are somehow delayed at CDG, an expensive cab (80-90 euros? Never took one) will save precious time.
Still, my recommendation is : "avoid, if you can".

Follow-up recommendation: allow 3 hours from plane to train at CDG, 4 hours from plane to train in downtown Paris.

https://www.paristoolkit.com/airport/paris_cdg_orly_bus.htm

Above outlines the choices

Rubber tires deal with congestion; rail has unhappy workers.... pick your poison

Some airlines close boarding 30 minutes prior to scheduled departure. Be sure you know what your 2nd flight requires and factor accordingly

I find the 4.5 hours scary short.

I second the 'find another solution' suggestion

Our last transfer using the Air France Le Bus Direct was 2 full hours on the bus midday. You never know when and where a jam will occur. I would allow 6 hours and just twiddle my thumbs at Orly. Can’t you get a flight from CDG?