Summary:
Godot 4 has encrypted PCK feature to protect game assets
Godot 3 has script encryption, though I’ve never seen it in action…
References:

Solution:
Here’s a snippet that adds --pck-key argument to pass PCK encryption key
Insert it to https://github.com/godotengine/godot/blob/4.4.1-stable/main/main.cpp#L1656

		} else if (arg == "--pck-key") {
			if (N) {
				String key_hex = N->get();
				N = N->next();
				if (key_hex.length() != 64) {
					OS::get_singleton()->print("Invalid PCK key: must be 64 hex characters (256-bit), aborting.\n");
					goto error;
				}
				for (int i = 0; i < 32; ++i) {
					unsigned long byte_val = strtoul(key_hex.substr(i * 2, 2).utf8().get_data(), nullptr, 16);
					if (byte_val > 255) {
						OS::get_singleton()->print("Invalid hex digit in PCK key, aborting.\n");
						goto error;
					}
					script_encryption_key[i] = static_cast<uint8_t>(byte_val);
				}
			} else {
				OS::get_singleton()->print("Missing value for --pck-key, aborting.\n");
				goto error;
			}

Samples:

(!NSFW) Vesper - Lust & Hunger
- Godot Engine v4.1.2
- Key: 524B982B805C74C0C015AD344111CA01FE96C45C892938DEBE3CAF0369981549
(!NSFW) Life with the tribe
- Godot Engine v4.2.1
- Key: 545CE6F51402E8DD937CB6A12B8750DBF10CEFA24B9E67841F7088EEAAA74043
(!NSFW) Five Nights at FuzzBoob’s
- Godot Engine v4.2.2
- Key: 99A4ECDC0D906B61F3BD0379B3E6490C0FF2B09EBF91F4F7D92918DCE973A900
MikuRPG Demo
- Godot Engine v4.4
- Key: 2C050C70F4839D1A832A60A1484E38334CF2A77DA7BF1711D0534D449FBF1924

Tests:
Vesper - Lust & Hunger, Life with the tribe and Five Nights at FuzzBoob's were tested on 4.2.2-stable

Without key	With key

MikuRPG Demo was tested on 4.4-stable

Without key	With key