When you ran npx create-remix@latest there were a few choices for hosting. You can run that again to create a new project, then copy over your app/ folder to the new project that's pre-configured for your target server.
cd ..
# create a new project, and pick a pre-configured host
npx create-remix@latest
cd my-new-remix-app
# remove the new project's app (not the old one!)
rm -rf app
# copy your app over
cp -R ../my-old-remix-app/app app