I personally have gotten some on Amazon most of mine are from there and almost all the “brands” are literally the exact same from china. I have a problem with blood pooling and these do in fact help me. I personally struggle wearing the 20-30 they just feel way too tight for me and I ended up not wearing them all day. I wear the 15-25 all day with no issues. So I can really only give advice on the 15-25 and they do truly help me. When I take them off I can feel my flood trickle back down more to my feet. I will also say I can tell a difference between the 15-25 and 20-30 so I would say they would compress more.

Edit to add these are my personal favorite:

Bluemaple 6 Pack Copper Compression Socks for Women and Men Circulation-Best Support for Medical, Running,Nursing,Athletic https://www.amazon.com/dp/B07X1N6BSD?ref_=cm_sw_r_apin_dp_JGPW2AGFDJTJ6K587QZP

Also if you like a certain style you can find all of these on Ali express in singles. Some I liked and some I would never wear so that’s another option. They are literally the same sock.