What are the risks of doing only in-depth interviews and surveys for user research?

I work at a very small, very scrappy software company as the only UX Researcher. There is such a huge need for information and a very fast pace of product development, so the easiest thing to do is rolling rounds of research with 6-8 users every month, plus a satisfaction survey sent to a random sample of users every month. So far it has been working quite well, given the team had no user research at all, but I'm worried about other valuable insights I might be missing if I only do IDIs and this survey. We do have a data team with more resources who run site metrics, as well as developers that do A/B testing, so my realm is mostly qualitative.

I am fairly new to UX Research, and I know there are fancy things like diary studies, personas, user journeys, etc, which all sound lovely but also time consuming. My question is, how dangerous is it (for product development and user empathy / understanding) to NOT make time for these other methods?