Since you are in your 40s here's what I recommend. You may not necessarily need all these steps but here's a good start.
I'm sure you have heard the cleanse, tone, moisturize method which you still need to apply to your routine, but now there are extra steps.
Cleanser: You didn't say your skin type in your bio but I'd recommend the youth to the people age prevention cleanser. It doesn't strip the skin of moisture and it's very natural. If you wear makeup daily then I'd suggest double cleansing. First I like to rub clinique take the day away cleansing balm gently over my skin then finish it off with my cleanser. There are so many cleansers out there so just choose the one for your skin type.
Toner: A lot of people seem to like the fresh rose toner at sephora but I personally use the thayer's rose toner (it's drugstore and gives the same results imo). Make sure your toner doesn't contain alcohol, as this is drying and prematurely aging.
Since you have sun damage you need to start apply a vitamin c and retinol to your regimen as well as a good SPF in the morning. I use the biossance vitamin c oil after cleansing in the morning. The drunk elephant vitamin C I like as well but you may use any that you like. Vitamin C helps protect you from sun damage. I also apply an SPF each morning. 90% of all aging is due to sun damage (yes even in the winter when we are barely outside).
At night apply a retinol. A good drugstore one is the roc deep wrinkle and my favorite one at sephora is the algenist firming serum. Start off by using a retinol 2-3 nights a week and see how your skin reacts. Retinols are very strong and some people may experience irritation if they start using every day. If you are still sensitive apply after your moisturizer at night. If retinols aren't your thing, I recommend glycolic acid like the drunk elephant. Use one or the other, not both. They are both powerful exfoliators.
Moisturize: It's great that you are using the argan oil, it's a very effective anti ager. I also love maracuja oil as well and like to apply it. I'd recommend a thick moisturizer at night and a gel one in the morning as they are lighter and don't look oily/greasy.
Oil: I apply oil last at night. There are several at sephora and they work well in combination with moisturizer. Herbivore makes lots of great ones.
Weekly Mask: I recommend the drunk elephant baby facial once a week or the herbivore blue tansy mask (do the same thing and are natural). You need a mask to exfoliate the skin. I also use some of the k beauty masks such as the egg masks and the laneige. They are affordable and I recommend you check them out. I also use charcoal masks if my skin feels clogged or my pores are large.
Eye cream: This is probably one of the most important steps you can do right now. The areas that show aging first are around our eyes, mouths, and necks (the skin is thinner there). Apply an eye cream morning at night. Also apply it around your mouth to help prevent lines.
Collagen: There are many liquid collagens out now and I'd definitely recommend one.
I use a derma roller before skinceuticals b e serum on certain nights. I'd also invest in some good supplements for the skin.
Don't neglect your hands either! Invest in a good hand cream too. Drink tons of water!
Hope this helps!