I found a solution that worked for me using Avast Premium 20
I combined a lot of the solutions mentioned here and tested with & without each of the below.
1. Go to Protection -> Firewall and set your Network to Private
2. Below that, click Settings and check Internet Connection Sharing Mode
3. On the same page, click System Rules and set both Allow Windows File and Printer sharing & Allow remote desktop connections to this computer to Enabled. Click OK
4. Click Packet Rules and add 4 new rules: (see attached image)
UDP Local port 67
UDP Local port 68
UDP Remote port 67
UDP Remote port 68
5. Restart your computer for settings to take effect.
The fourth instruction I didn't find on this forum, but I did see a mention of it on this page:
https://knowledge.broadcom.com/external/article?legacyId=tech234761 Not doing any one of these broke it for me...
Works for me, hope it helps you all!