I'm in my early 30s and looking to change 4 products in my make up bag, anyone with similar problems to mine below and can recommend produts that worked for them?
1. Foundation - I've got dry skin with visable pores and fine lines due to eczema
2. Concealer- specifically for bad under eye circles again caused by eczema
3. Mascara - I have extremely thin, short and straight eyelashes
4. Primer - something good for dry skin, visable pores and fine lines
We seem to have the same problem with eczema! I've suffered all my life with it but thankfully know how to contain flare ups.
This is what worked best for my dry, eczema prone skin:
Foundation - NARS Sheer Glow - Was absolutely amazing. Didnt settle in my lines and wasn't too dry for my skin either. I know you haven't mentioned powder but I highly recommend getting a good powder and baking your areas of concern with fine lines and dark circles but be sure to moisturise heavily. I use Aveeno and I find its the perfect under make up.
I use Estee Lauder Double Wear now as my everyday foundation - it has AMAZING coverage. I haven't gone back to NARS as my everyday since buying this 2 years ago. Its not drying either and ticks all the boxes. When my skin is drier than normal, at the end of the day, I do get some flaking but if you carry around a blender, it can be easily buffed away.
Concealer - I use a few different concealers but these are the main two. For concealing I use NARS radiance concealer (in the pot) and to brighten I use MAC 24 hour coverage which is amazing for under eyes. Does a much better job than my NARS at brightening up my under eyes. Feel like this step really ties my make up together.
Masara - I have given up here. I get lash extensions almost all the time. Like maybe 6 months of the year, I have them. When I dont have them, I use a mixture of 3 mascaras sometimes even more. To add curl, I use Lash Sensational - the rose gold one. To add length, I use Roller Lash or that Loreal one, its purple with the double sides. To add volume, I use Too Faced Better Than Sex mascara, Ted Baker, or Lancome. Those are the ones I'm using at the moment, so from any of them categories, I use one mascara. Keep a light hand, we dont wanna look like spider legs but be sure to use the one to add curl to separate your lashes too to avoid clumping.
Primer - I dont usually wear primer as I dont feel it does much at all. I used to wear Smashbox but I cant remember why I loved it so much

I would stress the powder/baking techniques for your under eyes, smile lines and maybe forehead. Leave it for a few minutes and then once brushed off the excess, I would say go in with some Mac Fix+ spray to add some hydration and life back in your face too. Also remember to prep you skin well too! Moisturise, moisturise, moisturise.