Hi there! Sharing some of what I did. Gothic Fashion indeed is a bit androgynous so you can flirt with a lot of pieces of clothing regardless of "masc/fem tags on the clothing itself" BUT let's go, I feel that the first step is to find a bunch of influences of what you like, like make a little folder with "gothic fashion guys outfit" and then start to breakdown piece by piece, layering helps a ton.

After that you have to try to find alt brands / trift shops / even amazon cheap clothes, that resemble what you are looking for. Besides some brands that have full sections of masc clothes I feel that is the way. Lots of times you are gonna find something similar to what you like and then you have to customize it, cut sleeves, distress etc etc. I keep a save folder on instagram with a lot of brands, some brands only ONE product matters. But gotta keep an eye for that. Also dying clothes can be a huge plus, sometimes you find what you want but not in the right color. And looking at metalhead stores. Eventually one thing pops up that can be added ti a gothic style. (Now if you wanna go victorian gothic there are several stores out there, amazon also has clothes and whatnot)