I've tried the generic's from the Dollar store once, they were suitable for use in a paint scraper, but not a DE razor. About 15 years ago a local Pharmacy was bought out by CVS, they were going to get their stock rotated from the corporate office, so they had a blow out sale. They had the old Gillette Blued blades in 10 packs (not SS or Platinum coated). These blades were from the mid to late 1970's. At a dollar a pop for 10 blades, I bought the1 remaining carton (48 count per carton) they had. 480 blades for $48. They didn't sell because they weren't SS or cartridges. These were the blades I started with when my beard grew in as a teen. 3 shaves, flip the blade, 2-3 more shaves then reload with a new blade. I used them in my Gillette Imperial Adjustable for years. When I bought a Merkur Futur, I tried the Blued Gillette blades in it. Razor Burn City....The Merkur blades worked fine in it, same with Feathers and Polsilver blades. The only other razor the Blued Gillette blades work well in is the Merkur 34C. Like vaping, Some combinations work well with tank and mod, some not so well.
Both of my son's use the Merkur's. One has a gold plated 34C I gave him for his 16th birthday, the other has a Merkur 180 (sensitive skin) that I also gave him on his 16th birthday. Both are in their mid 20's and still use the DE razors. My older son likes Wilkinson Sword blades in the 34C, my younger boy uses Merkur blades exclusively, he found that any other blade combo with his Merkur 180 tended to give him nasty razor burn. I guess you find the right blade/razor combination by trial and error.
I have a Slant bar razor by Merkur. The razor is incredibly aggressive, as close to a straight razor shave as you can get. It's great for a single pass shave, as I have a very thick and wiry beard. The only blades I can use in it that don't rip up my face are the Gillette Super thins, either Thai or Vietnamese.