I understand your frustration, as I'm pretty much in the same boat as well
I used to be able to clip Mocha's nails without much hassle, but ever since he had them clipped at the vet (it was included in his check-up), he never lets me get close to him with clippers. The vet used the same type and brand of clippers that I have, but she cut them on a different angle, which I think must've hurt him. So I do think there's a good chance that your baby probably had a bad experience getting them clipped at the vet.
Mocha's only 3lbs, so it's hard to hold him firmly because we're too afraid of hurting him. I've even had 2 other people help me and it's funny that 3 people can't hold down a 3lbs dog
Anyway, I bought a Peticure and I don't have much of a problem using it on his back feet. I do it with him standing on a grooming table. Unfortunately, his front feet are another story! It always ends up being a tiring, unsuccessful struggle. The other day, I tried clipping his front feet in the sink while he was getting a bath. I managed to get 2 of his nails clipped, which is more than I can get clipped on any other attempts. But, since that was only 20% successful, I gotta go on to the next thing....
I just recently bought one of those puppy purses, similar to these ones...
Puppy Purses at Paw Palace. I randomly found one at Walmart for $12
I'm going to sew on some type of cushion/padding around the leg openings so that it's a little more comfortable for him. Then I'm going to have someone "wear" him over their shoulder while I clip/file his nails. I figure it might be harder for him to struggle while he's suspended in mid-air. And, we won't have to worry about holding him down too firmly. Once I get the padding sewn on, I'm going to give it a try and I'll post about it on YT if it works!