How analyze the likert scale data with extra options of "don't know"?

Hello, I have trouble with my data analysis. I want to study consumer risk-benefit perception of GMOs. I conducted a survey using a questionnaire with a 7-point Likert scale, plus point 8 “I don’t know”. I believe the “don’t know” option is important because some of the items within the topic will not be familiar to the respondents, just in case they can select 8 “don’t know”. The issue is the percentage with selecting option 8 is higher, how I can treat this in the data analysis stage, I am using the SEM model, should I include, exclude, or else?

Hi, can you upload your data into google sheet and share please? Make sure the questions are also included