Okay, I don't really know how to start this, but here goes:

I'm a college-age trombonist looking to repair my current horn, a Bach 42BO purchased new in 2017 from my local band shop at a big sales event. Now, a year later, the slide is fighting back a little bit! Not sure if it's because of faulty construction or whatnot, but I've done a lot to try and get this slide back up and running: switched cases because I thought a ProTEC one was so small it was warping it, brought it to a local trusted repairsperson on three occasions, twice for dent/alignment check and once for an ultrasonic cleaning, and I sent it to the Slide Doctor in between all this. All in all, 6th position still feels rusty and, on bad days, if I leave the slide in 7th, it'll just sit there, rock solid.

I am exhausted. I don't know where to turn, I've spent copious amounts of money totaling almost the value of the slide at this point, and I'm at the point where I'm looking at selling some old horns to scrape the money up to buy a slide from a reputable company such as Edwards or Shires. I feel insane: am I doing something wrong?

I figured out a lot of the resistance I was getting from the slide was due to my usage of slide cream and me not being diligent about cleaning it off! I thought I could skirt by but that didn't work out, so I'm back to Slide-O (Black Cap). I now clean it twice a week with the good old cheese cloth rod, but even this is beginning to lose its effectiveness, and I'm now applying lubricant almost every half an hour and a quarter of a spray bottle of water to keep the slide barely working.

Things I haven't tried: Using Dawn dish soap as a grease remover, getting actual cheese cloth instead of old rags and using new cheese cloth every time I clean

I know I can do something! But I'm distressed at the moment.