So to wrap this story up, I went through the obfuscated parts and got the encrypted (and compressed) payload decrypted and extracted. It's essentially a "dead payload", pretty much only containing the icon of the executable; it contains no other notable resources, or even any code.
Based on the embedded payload's metadata, the obfuscation program used was made by a company called LogicNP Software, and is called something along the lines of Crypto Obfuscator For .Net (v2020)
(link to the product page). It only did some pretty basic obfuscation, to the point that I got through it with relative ease by just using ILSpy (and dnSpy), plus a couple hours of free time (probably way less would have sufficed, if I had actual experience in analyzing C# applications).
If anyone feels like reproducing my findings, they can just use dnSpy like I did (the x86 version, because this tool was compiled to prefer x86 for some reason), and put a breakpont on the line return memoryStream.ToArray(); in the method A.cd5aa3b8a1ae939d6d3a43c9aac5cb237.c9bc0aeef7e527f7935d4b45a818ed89a(), then step line-by-line until you can dump the byte array into a file. Do so, then load it back up in either dnSpy or ILSpy, and have a gander.
TL;DR: It's not malicious, just jank. Doesn't do anything other than what it advertises. Antivirus programs might flag it because of an obfuscator tool he mistakenly included with the application (misconfigured Visual Studio?).
Note: The analysis was done on the day I posted this, when the latest executable of that tool had the following hashes:
MD5: 2C4B955C4E67EE782ECB6EE69B8C7C9A
SHA-1: CC2BBFC9BF60D44BA79199B2B09ABBE50BE954D0
This analysis may not be valid at a later date, if the creater posts a new version of his tool. Compare hashes or reanalyze the executable yourself, if you think or know that a new version has been posted and are suspicious of the changes possibly made.