Where is the ethernet connection point on the iMac purchased in 2020? Do I need an adapter?

No you don't need an adapter, it is a standard RJ45 Ethernet port. It is on the back furthest to the left

Hope this helps.

Paul

A 2020 27" iMac has an Ethernet port on the back. It doesn't not need an adapter.

No you can connect it to the modem. No problem. Most modem route traffic as well.

Hope this helps.

Paul