Advice for a first time mom

Just looking for general advice or if anyone could relate. First time mom with an almost 2 year old boy who has been very challenging at every stage so far, he has a challenging defiant personality and trouble listening as well as some developmental delays and speech delays we’ve been working with therapists and he’s making a lot of progress but it’s still a lot of work for my husband and I. It takes a lot out of us but if we work together we get into some great routines and enjoy our time as a family so much.

So the question is, for those of you with more than one child, how do I know if I’m ready to have another child, when this already feels so tough for me? When I always wanted him to have a sibling but at the same time I feel too exhausted to even think about how I can manage it? Do I just tell myself I can get through it and it will get more manageable after a few years? Do I find more support and help? Do I just push through? Or do I consider that maybe I shouldn’t expand my family if I feel this way? I guess I’m just having a bit of a dilemma wondering if I really can manage it. I’m doing the best I can and want to be the best parent I can be in every single way for my son and if we have a future child for them too.