I would agree with BryceQuinlanTheFirst on introducing products slowly, that way if your skin reacts badly to any of them you know which one it is.
Also, you may end up peeling a bit from tretinoin for the first few weeks/ months so your skin might be a bit more sensitive, so vitamin c serum or acids might just irritate it more. Basically it's a bit of trial and error, but once you have found a simple routine that works, it's fairly easy.
For example in the Morning I use:
Geek & Gorgeous Vitamin C serum
SPF 50+ sunscreen
Cerave Moisturiser.
In the Evening:
Pixi Rose cream cleanser
Prescription strength tretinoin (0.05%)
Cerave Moisturiser.
Both take around 5 minutes morning and evening and this routine really works for me as it's easy and no fuss.
I have been using tretinoin for about 3 years now and I really like the results. I usually apply it 5 or 6 nights a week, but I have been on it for a long time so I can use nightly with no irritation - I had to start out at once a week, then twice a week, then three times etc. to build up tolerance over several months, I also started out at a lower strength and moved up slowly.
Tretinoin has decades of clinical research behind it to show that it does give really good results, but only if you use it consistently over a long period of time, so be patient. Your subscription service should increase the percentage after a few months to a bit stronger. It's not a miracle cream, you're not going to look 20 years younger or anything, but my skin is brighter, clearer, and any dullness and fine lines I had starting to appear (I'm 38) have definitely lessened. Mostly my skin just looks plump and dewy and better than it did a few years ago.
On nights I don't use tretinoin, I will sometimes use Glycolic acid for exfoliation, but I only use it once a week or so and I don't find I really need it that much, also don't want to over irritate my skin. I also have a few other serums which I use sometimes (niacinamide, peptides etc,) but I feel like those are in the category of 'nice to have, but don't do that much'.