Hi OP. I began tretinoin via a dermatologist prescription last year. I can't remember the brand (Spanish) but it was a 0.05% concentration. That went fine so I was happy to switch to the online pharma providers and opted for Dermatica. I use their 0.1% tretinoin serum on my face (not neck) and the back of my hands, probably 4 times a week, rather than daily. Otherwise just wash with Atoderm moisturising oil, Cerave moisturiser morning and night, SPF50 in the morning and Vit C serum (from Superdrug) at 20%.
I've been doing this for 6-7 months and areas of pigmentation (sun damage, the odd bit of post-inflammatory hyperpigmentation) have diminished. The texture of my skin is very nice - the 'glow' that people talk about with tret is, I think, down to higher cell turnover, so you don't have an extra layer of tiny ashy dead skin cells (obviously you do have dead skin cells around - what do you think the dust in your house mostly comprises?) clinging on, and therefore your skin is more reflective of whatever light is around. This extra luminosity is probably what makes fine lines less visible as well - I don't have the tools to calibrate any change in depth or length of said lines, so it's all very subjective!
Make-up, if you wear it, sits better, the light bounces off your cheekbones, you just look a bit more 'on'. If you do Zoom/Teams calls, you might notice you look better on the screen! My mother (always an enthusiastic observer and critic of her children) tells me I look well, my skin looks really nice.
So, I would say it's worth giving a good shot for at least 6 months. I don't suppose the formula varies much between suppliers, so I'd go with the cheapest or most flexible subscription.