(I follow you on dA and haven't read your comic, but totally stalk all your art and con announcements and have for years lol)
Actually you can upload to insta from your computer without a 3rd party application. You just need chromium type browser up, go to instragram and hit F12 or so to get the inspect element window open, where you can adjust which smartphone to emulate. Totally free, built into the chromium (so Brave and Chrome both have it). You might need to hit refresh for the lil upload icon to appear, but it works even on my win7 laptop of ancient age.
I agree about dA being a better portfolio site. Gallery folders, Scraps, and Featured are the best things done to the portfolio UI there overall. Every other site I've been to pales in comparison for clean neat organization.
I mean, look at this. You can even adjust folders to have thumbnails, details and names -all for FREEEEEEEE