Is he interested or am i just reading it wrong

I’ve known this guy for about 2 years now. But it was only 10 months ago that we began obviously flirting and showing interest in each other. We see each other on campus but he reached out to me via messenger and we have been speaking on there. From the way he acts and the interest he has shown, I expected him to ask me for my number and set up a date. But he only ever contacts me on messenger, which I consider a red flag. He always seems very keen on me and is always telling me to call him if i need help with anything (we are students) and is always available to help me study if I contact him. I get the feeling he is using study as an excuse to spend time with me. when he comes over to help me study he stays for ages and almost does not want to leave. We have not kissed or been intimate as I will only do that is I see some commitment on his part. ‘ve started getting annoyed that he never seems to progress this ”situations ship”. If I don’t contact him, there is silence. He asked me to lunch after i contact him on messenger after a couple of weeks but I declined. The second time he asked me to lunch was after another period of no contact and just randomly bumping into each other. I declined again as it seemed he was just asking me on the spur of the moment and I was just an after thought. Is he sending me mixed signals or am I just not seeing that he’s not that into me?