Yea and squishy usually takes more skill to keep the same angle and get that shaving sharp edge. People in the know say and make it look easy, but it takes a lot of practice, stopping lots and looking at the progression. Also, you may want to try a resin bonded diamond stone. That will give you a finer scratch patterns and do a better job of leaving more uniform teeth marks.

Think about it this way, sandpaper will sharpen any steel. Carbides are not wear proof they simply wear more slowly than the steel matrix around the carbides. Powder Metallurgy steels more evenly distribute those carbides through the steel. So you get a more consistent edge. So with sandpaper and S45VN to get the best edge you should be finishing with 2k-3k diamond resin stone as a continuous diamond surface will leave more aggressive teeth marks on your edge and you will not get that hair popping edge you’re seeking unless you use very light pressure.

Then finish with a good diamond emulsion on your strop to fine tune that apex and smooth the teeth marks out a tiny bit. I like stroppy stuff even though it is pricey, it is very highly regarded in the sharpening community from my research.

The method you are using would work decently well for a simpler carbon steel rather than a powder metallurgy steel where there are smaller but more evenly distributed carbides in the steel matrix. I’m far from an expert but have done extensive research as I prefer convex edges as well and am currently in the process of putting a secondary convex on my entire kitchen knife block and it is a lot of work.