There are several factors that can contribute to your domain authority not increasing despite acquiring links over a 200-day period. Here are some potential reasons to consider:

Quantity vs. Quality of Links: It's not just about the number of links pointing to your website, but also the quality and relevance of those links. If the links you've acquired are from low-quality or spammy websites, or if they are unrelated to your industry or content, they may not contribute much to your domain authority.

Link Diversity: Having a diverse and natural link profile is important for building domain authority. If a large portion of your acquired links come from a single source or have the same anchor text, search engines may view them as unnatural or manipulative. Aim for a variety of high-quality links from different domains and sources.