Deep Snow is one of the features to come in the Mountains Update and I think this is going to cause a lot of problems and obstacles in Cold Snowy Biomes. A solution to this would be an item that a player should wear, but instead of implementing a new item, we should look for what we already have which is the Frostwalker Boots. We already have Boats which is easier to obtain and makes Frostwalker Boots quite useless so I made this suggestion because I think it would give Frostwalker Boots a better purpose and many players would actually want and need to use it when exploring Snowy Biomes. A Player wearing Boots with Frostwalker Enchantment should be able to walk on Deep, Snowier Snow without sinking into it.
Thanks for listening to our Feedbacks Minecraft Devs!