Hello @loribroda, I've been using a CPAP regularly for about 3 years. I had what you might call vivid dreams or nightmares off and on even before using a CPAP. I still might have one once in awhile but they aren't as regular and often. Here are a couple of articles on using CPAPs and dreams that I thought you might find interesting and maybe helpful.

— Changes in dreaming induced by CPAP in severe obstructive sleep apnea syndrome patients: https://pubmed.ncbi.nlm.nih.gov/17118100/
— The Mind Revealed: Learn More About Sleep Apnea Dreams and Nightmares: https://www.cpap.com/blog/sleep-apnea-dreams-and-nightmares/

Here's an article that has a few things to try that might be helpful.
-- What causes vivid dreams? - Medical News Today: https://www.medicalnewstoday.com/articles/325396

One of the things mentioned that really has helped me is setting a regular time for going to bed and waking up. Also avoiding coffee and exercise just before going to bed.