Trek7200: new bracket,crank,chain,&shift cables. Deraillers set Trek manual. Good stand results, but stumbles riding up incline
If indeed the &quot;stumbles&quot; refer to the chain skipping on the rear cassette gear, a simple fix is to replace the cassette. I note that the cassette (8 speed seemingly from what I find on the net) is the part of the drivetrain that you did not mention changing. Its gears wear just as do the chainrings on the crank. Similarly to the crankset, the middle gears tend to wear the most as they are the most frequently used.  The cassette gears and chainrings would have worn along with your previous chain, and now the new unworn chain matches the new chainrings, but not the still-worn cassette gears.
Thus, the chain is likely skipping over the still-worn cassette gear teeth, especially (or only) when under load.