It sounds like you’re already at a pretty good weight, you just want to recomp some fat with muscle. You can add IF if you really want, but mostly I would just start doing some resistance training and making sure you’re getting enough protein. You don’t need to bulk to build muscle.
You can do IF, but it sounds like you need to look more into Strength Training. It’s all about low-weight, high-rep exercises.
If can help your body composition stay lean, but it won’t help you change your muscles on its own.
Start with 30 sit-ups and 30 push-ups every day. If you can’t do them all at once do them, say, 10 at a time. Pretty soon you will be able to do all 60 in a row. This will help your stomach and your arms. I don’t want my muscles to show but they are definitely there now after only a few months.