Anyone know anything about disc brakes?

I think what you need to do is let all the fluid out, take the caliper off, put it in the bin and fit shimano.
I have Sram brakes on 2 bikes and dread the day they need servicing

Just for balance I have ran these same Force hydro calipers previously, no longer have them though, but run sram red hydro and sram brakes on all 3 of my mountain bikes.

Its possible that the pistons and seals need replaced but I've only ever replaced the pistons and seals on one Sram caliper in my years of owning them. So it might not be necessary yet.

I've found that following the piston advancement process several times in a row is whats needed to get them back to retracting properly. I use this handy tool when servicing the code calipers. But they dont have one for the force caliper but its not really needed if you have the correct pad spacer.

I'd advance one piston out and use a cotton bud dipped in dot fluid and really give it a good wipe. Push the piston all the way back in and then advance it again and clean it up again with a fresh cotton bud dipped in dot fluid. Do this at least 5 or 6 times - more if you can be bothered. Then repeat the process for the other piston then do a full bleed.

I've used this process before but instead if dipping the cotton bud in dot fluid I've smeared the tiniest amount of red dot compatible grease on it and smeared it round the piston and pushed it in then advanced, repeated that a few times then advance a final time and wipe it with dot fluid, press back in then bleed.
The dot compatible grease method isn't everyones cup of tea since if you use too much it can of course attract dirt - this is why its good to wipe it off with dot fluid on the final run.

I think I can agree with Phil in that the servicing can be a bit more involved but if its done correctly they work very well.

Edit - another option is using disc brake cleaner on a cotton bud instead of dot fluid then use dot fluid on the final advancement

Another edit - if the dot fluid only method doesnt help much then try the dot grease method, I've got some I can give to you if needed, I bought a 25g tub but 25g is enough to do literally thousands of calipers...