I’m 10 DPO from full TT, muscle repair and Lipo to flanks. Is tummy supposed to be firm right after a tummy tuck? (photo)

Firmness and hardness are subjective terms.  The photo you provided is still early and has a great deal of swelling.  This may produce an outstanding result if you were to fast forward 3 months.  Some PSs produce very flat, very tight-looking results, whereas others are more conservative in the amounts of skin and fat they take out. Rather than compare your recovery to others, I would continue to follow your PS's post operative guidelines and follow up with him/her to allay your concerns.

Swelling and bruising are common after a tummy tuck and can take several weeks to resolve. If you do have a seroma it can typically be addressed in your surgeon's office. It is not always associated with fever or pain. It's best to visit with your surgeon who can help determine if there is a cause for concern.

Hello dear!!
Thanks for the question and provided information as well.
You are still early on the healing process, it can take up to six months to see your final results, so please be patient. At the stage you are in, inflammation is normal. It is not suppose to be firm right after surgery.
If you have any concerns, please follow up close with your plastic surgeon.
Good luck :)