We are buying Mikrotik fiber switch, CRS326-24S+2Q+RM. And we are about to buy the SFP+ transcoder and the one on the market today (I'm talking about Brazil) is from the Ubiquiti brand, the UACC-OM-SM-10G-S-2. Does anyone have experience with this "combination"? Or if you have positive reports (or not) with the "similar combination", between the mikrotik switch and ubiquiti transcoder.

No experiance at all, I know it doesnt help with this case but in the future there is mikrotik help page with some 3rd party vendor peripherals and if they are supported or not:
https://help.mikrotik.com/docs/display/ROS/Peripherals