Flush stomas are a real pain in your new arsehole. I know I have a near flush one myself in a belly fold.
Ideally, it's best to get a revision, where they make the stoma stick out further, about 3/4 of an inch. But like you, I don't want to do any more surgery.
I didn't much care for the stiff Hollister products supplied by my first hospital, and when I went to a much better hospital for an ER visit, they put a Coloplast Sensura Mio one-piece convex on with a four-hook belt and barrier strips (flange extenders) all around, and I couldn't be happier.
The thing was, I was still having issues because of my belly fold, but I remedied that by horizontally weakening the convex wafer bubble so it's more flexible.
I also learned to clean the stoma area using liquid antibacterial soap as that does a good job of disinfecting the wounds of digestive enzymes and dries out the wounds some so paste can adhere to it.
I can second the use of a blow dryer and finger drag testing the skin so it isn't slippery. If a spewing occurs on the skin, it's back into the shower to start over again.
I use Coloplast no sting paste, but just before applying, I mix a small amount of stoma powder into it to make it more sticky and set up faster, then apply only a thin coat around the stoma, focusing on wounds to ensure it sticks first, or else I remove it and discard, blow dry the area some more, and try again.
Once I do that, then I use 1/4 cut barrier strips and place the curved part around the stoma, pressing the thin coat of paste down onto the skin. I do this twice around the stoma.
I fill my belly button with some toilet paper to level and a 1/4 piece of barrier strip over that to level as it tends to grab onto my scar tissue there and be irritating.
Then on the convex wafer bubble, I remove the backing and apply two thick rings on the outer edge area of the convex bubble (not too close to the inside) and score them using a flat stick, mix some stoma powder into them, and then stick it on. Ensuring when I press down that I'm not covering the stoma, or else I have to put a long stick up in there from the bottom of the bag and scrape excess away.
Then once the wafer is down, I put full-sized barrier strips all around. Then wait, laying on my back until the paste sets up, or else it will run out.
Once the paste has set hard, about a few hours later, then I put the belt on and not too tight, just snug. Then I can move around.
Unfortunately, because this process takes so long, I have to carefully time my bag changes with fasting and eating only something that really thickens the stool, usually applesauce or bananas does the trick. If leakage occurs during this process, I have to remove everything and start all over again.
But I do get 4-7 days out of a wafer/bag.
I wash mine on the toilet from the bottom using two drops of antibacterial dish soap and a water bottle. Rinse. Then one drop and a little water to mix with future output so the smell doesn't cause me to choke to death on the fumes next dump time.
What is good about this process is if I spring a leak between the wafer and the cut barrier strips, since I've created a pocket, it holds the spew, protects the skin, and doesn't make a huge mess.
My only trouble has been tiny leaks around the stoma due to the stress of bending over, etc., which I'm getting better at remedying.
They do sell a suction machine online that could suck up more liquid-like spew as soon as it appears out of the stoma before it hits the skin, but any solids tend to clog it.
There is this tube thing that one presses up against it to collect spew so it doesn't get on the skin, but it's only for round stomas and not oval like mine. So I'm working on a solution like that using a heated plastic PVC pipe to make it more oval, put the precut wafer hole on it, and try it that way.
So I'm working on perfecting this process, it hasn't been easy, but at least I'm getting several days out of a wafer and feel almost normal and not a slave to changing it every day or even more like some do with near flush stomas.
And yes, I do second using nothing but plain soap around the stoma because the skin needs to be dry, clean, dust-free, and especially oil-free for the adhesive to stick. Spew contains oils and has to be removed again by washing. I don't advise using rubbing alcohol as it stings and gets trapped underneath and keeps on stinging.
If you're drinking coffee, you may want to switch to tea, as coffee makes the burns much worse. However, tea, like other caffeine products, can cause diarrhea-like symptoms where the stoma will spew for hours afterward, so time tea consumption on a good bag or wind up sitting in the shower for hours on end.