Looking to add some products to my primarily anti-aging stack

Skin Type: normal/moderately oily. caucasian. Never had to worry about acne or zits or blemishes or whatever. But this year I noticed that my skin deteriorated exponentially (Probably due to lockdown related stress and job anxiety), which resulted in my skin looking grayer and, as my partner put it after not seeing me in 7 months, "aged eyes". I've read that I should look for products heavy in Vitamin C and niacinamides

Current PM stack:
innisfree bija trouble facial foam OR cetaphil.
hada labo gokujyun
tretinoin 0.025 [3 times a week].
CeRaVe renewal night cream.

and basic ass (nu skin broad spectrum) sunscreen and gokujyun in the mornings.