I have been using a 1" x 30" belt sander like this (
1x30 Belt sander) for many years. My blades are always hair shaving sharp.
Here's another
https://www.homedepot.com/p/WEN-1-in-x-30-in-Belt-Sander-with-5-in-Sanding-Disc-6515T/307873039
The trick is not the brand of sander you have as much as it is the belts. I have several belts now 120, 240, 320, 400, 600, 800, 1000 and leather with polishing rouge. I got all of them from Lee Valley Tools.
I also have many good stones, but that requires alot of elbow grease especially when beginning with a badly sharpened or badly dull blade.
I'll use the stones to touch up a slightly dull blade, but I'll still always finish with the leather belt on the belt sander for that mirror finish. I don't buy stones that are sold in sporting goods stores or knife shops. Instead I get them at industrial supply stores that specialize in abrasives where the quality is excellent but the prices are much much better. Hopefully there's one near you.
I would advise you guys to buy a generic power tool such as this belt sander where you can get belts at the local hardware store, rather than some niche product with hard to find or limited selection of belts. It's very important to have the fine belts and leather for a razor edge.
You learn a lot about blade steel when you have a belt grinder as you learn what steel throws a large burr or not. Often times a cheap knife well sharpened is an awesome knife. Case in point, I bought a Shimano fillet knife at the dollar store (actually I have several now). Out of the box it was crap, but excellent after I re-profiled the grind angles and polished the edge. When I was done, it was like a brand new Mora.
I don't believe it is important to obsess about the exact grind angles or tools sold in an effort to help you maintain an angle. You'll get a feel for it anyway.
If you think about it, it is very difficult to sharpen a blunt edge, but less work to touch up the edge if the angle is slightly too slight... So err on too sharp rather than too blunt. I hope this statement makes sense for you guys.
Here's a couple pictures of a beast of a survival knife I made last year from 1/4" D2 steel. It's an awesome blade with a hybridized full flat grind / Scandi grind. I made the canvas Micarta too. Soon I'll need to take the handle scales off and polish it up again.