I’m not a specialist in this field, but I found your question to be really interesting. I did a search online on this matter, and I found out that there are some relevant articles and videos explaining how to normalize the sound level. Of course, there is always the option of hiring professionals who will solve this kind of problem. I know my relatives back in the UK faced a similar issue at their church, and they hired guys from https://www.ontourevents.co.uk/conference-audio-visual-hire because they had a very good reputation, and in the end, they did a great job. Wish you all the best!
