Got a 2022 zforce800.  Has about 600 miles on it. Water/mud got into the external clutch/belt housing. Cleaned housing out.  Belt looks in good shape.  With engine on, shift from any selection is extremely hard. And clutch tries to disengage right off idle.  Jacked rear end off ground and ran.  With engine on I can shift thru all selections As long as I do not apply brake.  When brake is applied, shifting becomes almost impossible.

What steps should I take to get this fixed?

Thank you all

[2015 Z Force 800 53/Trail EPS]

If you shift it while the drive train is rotating you are damaging transmission parts like the fork(s), gear dogs and gear teeth. DO NOT ever shift it while moving. Now...it's hard to shift because power or force is being applied to the belt while it's supposed to be disengaged from sheaves. This can happen if the idle is too high, which means a problem with the IACV, throttle cable or throttle e-module. In units with a wet clutch is can mean a spring has come loose from one of the shoes or a bearing on the half-shaft is failing. On units with no wet clutch, and ones that have had water or mud intrusion, can mean the idler bearing is seizing up. In 2022 there were both wet clutch 800s and dry clutch 800s. I suspect yours may be the dry type. If there is a retainer bolt in the center shaft and a larger nut outside of that, it's a dry clutch and I would be looking at the bearing the belt rides on at idle. All of them fail quickly.