Why not use Zoom/Skype and Chessbase to deliver lectures? It works well for the Juniors to Masters program which Victoria Doknjas can fill you in on.
If you just want online resources chess.com and lichess.org have lots of bells and whistles. Chessable, now owned by chess.com is pretty good. Modern-chess.com, Limitlesschess (or improvemychess.com also by Mesgen Amanov), ForwardChess.com are all very useful sites. In most of those cases you have to buy things to get much use out of them.
For beginners this app is very interesting and entertaining:
www.chessmatec.com,
https://www.campus.chessmatec.com
Our contact there is Ariella Alterman daughter of the well known grandmaster who is also involved in this family business. We were talking to them in 2020 during the height of the pandemic. Vlad Rekhson was using it with some of his classes, I believe.