Long time ago, pre-dating these high power smart phones I created kml of MT Bathymetry per FWP Regions so it can open on our old crap smart phones. Then sometime in 2018-19 FWP actually allow you to download kml directly from their GIS library. A quick search today and that function is currently unavailable, although you can still download the shapefile zipfile on a desktop/laptop (was not able on phone). The attributes show newly created lakes as of 11/12/21. One of the lake that jumped out was Hebgen Lake that was not in my 2015 data.
All that being said, do yourself a favor and buy Navionics or use their free chartviewer to get rough idea. GPS Nautical Chart is also a good one too. Good luck on your search!