Simple Routine Help

Hi! I am 31 and I'm starting to implement a skin care routine for the first time. Currently I use toner in the morning and then sunscreen, and in the evening I remove makeup with micellar water, then use toner, then put on a a moisturizer (NYM fundamental night cream). I would like to add a serum to my evening routine, but I am so lost! Retinol seems a bit complicated and I don't religiously do my routine every night so I'd rather avoid it. Would you recommend I add a vitamin C serum? A hyaluronic acid serum? Something else? What's best for preventing wrinkles and fine lines? Thanks for any advice!

P.S. I tend to have oily skin, especially in the summer.