There are other ways to manage ADHD for sure. Medication is one of the first line and most effective treatments but there are a number of other options, skills, and tools.
It would be important to first identify what some of the most common symptoms and challenges are for you. For example, if it’s restlessness and hyperactivity, exercise may be a good option. If it’s organization, getting an ADHD coach could be useful. If it’s struggling with motivation or work, there are some great tools on the HowToADHD Youtube. If it’s about relationships, there are some good books out there as well as resources from here in the support forums.
Bottom line, yes you can help treat ADHD without medication. It may not be as effective, but it can help manage some of the concerns and offer extra skills and support in your daily life that may also improve your other conditions.