Bellflower - slvness review for Vitamin C 20% Serum

newbie on Vitamin C serum, I got confused when I read about the do and donts on Vitamin C. Some say yes to mix it with this and that, some say not to mix this with that 😂 For example, as I understand we should never mix Vitamin C and Retinol, because both are active ingredients. Also, never layer Vitamin C with Niacinamide, as I read on L'officiel. So I only use this serum with Hyaluronic Acid (+ sunscreen). This serum is bit waterish even though the texture seems thick. Easy to absorb. I love the way my skin feels whenever I wake up. I use it on PM.