It sounds as though you would be motivated by altruistic reasons and not for financial benefit OP, but you obviously have a young child now and hopes for another so I would concentrate on your own family, as there are so many unknowns between now and whenever you might embark on this. You may not have an easy pregnancy next time and not want to go through the morning sickness carting for, one hopes, two children, for anyone!
In the meantime you will have lots of time for reading! You may struggle to find more on the down sides of surrogacy as the media perpetuates the idea of it being a wonderful thing (I make no secret of being anti-surrogacy) and agencies and lawyers who benefit financially from surrogacy are of course going to be biased so it will do you well to do your own research.
I am anti-surrogacy, for many reasons, but mainly because the baby cannot consent. With your 2yo was there ever a time your newborn wouldn't settle with anyone but you? Not even your husband? Sometimes a baby just wants it's mother. There aren't many things a newborn knows, how to feed and poo, and who it's mother is. You probably already know about the 4th trimester.
I've read about donor conceived children and their distress and of Jessica Kerns who was told she had colic as a baby, when she believed she was missing her mother. Her story is a tragic one, I would suggest looking it up her speech to Congress for more. I also recommend Renate Klein's book and Unexpected Mother by Susan A Ring.
Many stories I read about surrogate mothers and surrogacy focus on the commissioning parents desires (or 'needs' and 'rights') and not the mother, and the baby is often the prize at the end. Sometime there are scarce details of miscarriage or health issues. You now have time to read all about the process, the drugs, the implantation and the further drugs you have to take so as not to reject a donor egg (I assume you wouldn't use your own as the child would be related to your own child/ren), about foetal reduction (fatal injection to the heart in the womb) and about the extra risks related to a surrogacy pregnancy, parental orders and the legal process.
I also wonder how, if the relationship with the family you helped create breaks down if there wouldn't be depression and loss, or would it be perhaps worse if you knew them and saw the family break up or if the child was raised stricter than you envisaged, how would you feel?
There are many threads to read through and some more material I could provide if you're interested please DM me. MN can be thought of as anti-surrogacy but there is good reason for that and I imagine you will want all information made available to you so you can make an informed decision.