I've built images of 21.02.1 for WNR1000v2, WNR2000v3, and WNR612v2 for testing. These images do not include PPP, SSL, OPKG or Relayd like the 19.07.X series. They include LuCi, IPv6.
I have not been able to test these images as I no longer access to these routers - use and flash at your own risk.
(21.02.1 Link Removed)
Backup your configuration via webserver, but flash new upgrades using SSH! Flashing via LuCi webserver most likely doesn't have enough memory to handle file upload.
Please report back with your comments in this thread and tell us if these images flash successfully and your device runs reliably.
(The WNR1000v2-vc and WPN82N are not available as their device profiles have not been submitted to the Openwrt codebase for the ath79 platform. Please submit these device profiles if you know how. Thanks to user Ashus and this thread for his helpful information in configuring size optimization options for 21.02. He has also successfully created his own 21.02 images for WNR1000v2, WNR2000v3, and WNR612v2 that you can try.)