CDG time and baggage management

Since Air France and Delta are partners, I think you might be able to check your luggage in Marseille all the way to the US, especially if the CDG-USA leg is an Air France operated flight. I have no firsthand experience of this, so perhaps somebody else can confirm.
If not, I do worry that ~3 hours between flights is not quite enough to be safe, because it would be recommended to arrive at terminal 2E 3 hours before if you were "just" flying CDG-USA, and it will definitely take about 45 minutes to deplane, get luggage and head from 2F to 2E. Is there any way you could rebook to an earlier flight to CDG? Or even rebook to have everything one ticket, assuming the fare difference is reasonable?
Also, base fares for domestic flights do not include checked luggage, so that will cost extra.

This is risky for a high-stakes flight. If you have to check a bag Marseille to Paris, you need to leave the secure area to get it, go back upstairs to check-in for the second flight, go through passport and security. That's okay so far, but what happens if your flight is delayed? If you don't check a bag, you'll save about 20-30 minutes and all is okay. But, again, what happens if your first flight is delayed? With two disconnected tickets bought from two different airlines, even if they are practically the same, means that if you miss the return flight, you are not protected and need to buy a new return.

However, perhaps Delta will be willing to link the flights. It's worth a call or two. That changes everything.

If the two Tix remain unlinked, consider taking the train to Paris the evening before.

We are taking this flight, but there was another Air France flight leaving Marseille about 90 minutes earlier. Is that an option for you?

Thanks for this advice, it's very helpful! I will look into an earlier flight or even perhaps a train, which would let me keep baggage with me. This will be in June so available flights may vary, and I'm noticing that flight times are changing week to week so there's really a level of uncertainty. I'll plan for more time at CDG to allow some breathing room.
Looking at the CDG website for the terminals, I thought there might be a baggage pickup near Terminals 2E and 2F, so that I wouldn't need to go through security. Sounds like that's not the case so I'll plan accordingly!
I'll also look at booking two one-ways and see if I can get a connecting flight from Marseilles to home (Portland OR). Prices seem to be moving around, higher today.

Careful with the train. Two days ago our 90 minute ride on the Intercités from Marseille to Montpellier was an additional 90 minutes late. Someone had left a package on a previous run, shutting down all traffic on the Marseille-Bordeaux tracks until the bomb squad could deal with it. Last week a Marseille-Paris TGV hit a boar in the Yonne and a Montpellier-Paris TGV had the electricity fail.
I'd still go to Paris to be in place the night before.

I completed my trip and am reporting my experience for anyone interested. The advice I received here was very helpful!
June 22, I took an earlier flight from Marseille to CDG, allowing about a 4 hour layover. This flight was delayed an hour and a half, and we arrived at CDG an hour late. My friends who had a shorter connection made flights to the US, barely.
My flight to the US was also an hour late departing, and arrived in Detroit an hour late. I had a 1.5 hour layover there but needed to retrieve my bag and go through customs. After rechecking my bag (at departure time for the next flight) I saw that my flight to Portland was delayed 20 minutes so I ran full tilt, and I think they waited for me. I was the last person to board.
A longer connection time in Detroit would have been helpful too.
I did get home an hour late, but without missing any flights or losing my bag. It was 23 hours of travel time.
Things that helped:
I was able to link the Marseille Air France to Paris CDG flight and have my checked bag transferred at all connections. This took effort. I called Delta weeks before leaving the US to do this, and phone lines were not available. I was advised to communicate by text and did so, referred several times to get to my specific question answered, with long waits between replies. The texting process took 6 hours - fortunately I had started the process in early afternoon and was able to watch my phone.
Also, I used the Delta flight app which showed me gates for my departing flights before they were posted on monitors. Also I was able to track my luggage and make sure it was traveling with me.
Overall a difficult but successful travel day, at a time when flights and airports were notoriously stressed.

Thanks for the follow up and glad things sort of worked out for you.

Thank you for sharing your experience.
Flights these days are not for the feint of heart!
Well done!