I'd recommend picking up Xraym's premium scripts for Reaper to PT conversion here:
https://www.extremraym.com/en/downlo...-attranslator/
These basically take anything in your project that'll conflict with Pro Tools and select them so you can export them as a new take. They are pretty comprehensive, and I've had good success with them so far. This will find anything that has pitch/timing adjustments, accidental short clips hiding underneath edits, items with Take FX, etc.
For most all FX work, you're going to want to do as "take fx" and render each item as a new take as you go, since the re-recording mix is going to be done in PT and none of your plugins will translate to PT.
If you're working in surround, you're going to want to reroute most everything to PT's surround channel order, which is different than pretty much every other application's. So instead of SMPTE routing (L,R,C,LFE,Ls,Rs), you'll want it to be in Film order (L,C,R,Ls,Rs,LFE).
Definitely keep mono/stereo/surround tracks separate. PT won't know how to handle tracks with mixed channel count items.
It feels kinda like working with an arm tied behind your back when you're working in Reaper knowing that its going to have to go through Pro Tools, but it can be done. Hopefully Reaper catches on with enough mixers someday that this will no longer be an issue!