On my iPad I have Lightroom setting Only Download Smart Previews set to off.
Today I loaded 3 raw into Lightroom on m iPad. Later i went to my iMac desktop and opened Lightroom Classic and there are my raw files synced. Next I edited all 3 files in Photoshop and they where sent back to Lightroom Classic and put them into a collection that syncs to the iPad.
They did sync and I see them on my iPad however the quality does not match what I see on the desktop.
I ended up exporting these 3 psd files as full resolution jpgs from Lightroom Classic and then airdropped them to m iPad. The quality of these images look good.
Syncing Collections from Classic to the Cloud only syncs lower res Smart Previews.
Depending on what else you are using Classic for, could not also install the Cloud Based Lightroom on your computer and edit in Photoshop from there? Then they would be in the Cloud at full resolution.
Assuming you have the 1TB Photography Plan, then Lightroom Desktop would be included.
Think of it as Lightroom Mobile for Desktop (with a few more features). It does keep its own internal catalog locally but generally you wouldn't touch this. It's mainly contains the local cache (the amount of cache can be set in the preferences if you want to save HD space).
The full res files remain in the Cloud, but are downloaded locally for certain functions (including editing in Photoshop).