I just completed the swap yesterday on my 2020 GTI.
It took about 2h total and the most time was spent cursing and trying to first get the fan shroud and later the alternator out.
For anyone that's trying to do this, once you unbolt the alternator and disconnect the harness and wire, the only way i found viable was to not turn the alternator in any way but get it out between the AC hose and the radiator. Keep the alternator upright almost in the same position that it's mounted to the block and just tilt as needed to clear the hoses. Yes, you need to muscle the hoses a bit but keeping it in this direction was the only way for me to get it out.
I spent about an hour flipping it around and trying other ways and ultimately this is the only one that worked for me.
Once the old one was out, putting the new one in was a breeze.