Thanks to a mod called FakeBlocks, you can create blocks that you can walk through. In fact, they can be distinguished, but a beginner is unlikely to be able to do this.
FakeBlocks Mod for Minecraft 1.16.4/1.16.3
To do this, a new block will appear in the game that will look like a transparent structure. First, you need to install a fake block and put any other in its place, and now it will be absolutely transparent.
1.16.4 – FakeBlocks-Mod-1.16.4
1.16.3 – FakeBlocks-Mod-1.16.3