I had a 980 FE and it was begging for mercy, you can get good frames on 1080p, low settings, if your card has good cooler, so it won't turn into a grilling pan. But i would suggest upgrading even with a second hand part (i got myself a second hand palit 3070 jet stream, it is a trooper, but the cooler can't keep up with the heat at times.) so yeah, that's that.
I should add games like csgo, fortnite, rainbow, gta v, rdr2, skyrim runs fine on a 4gb but still...
You are right, I've mistaken o(￣▽￣)ブ it seems they no longer shared the source code with the public around 2016 (what ever came after version 3.x) but they forgot to remove GNU-GPL from their website until 2020... still, it's the best alternative I managed to find for IDM. There's a bunch more like Motrix, uGet, Jdownloader etc... but they're too finicky for me to deal with... I would love to get some recommendation if anyone has one...