@davidc502 stopped building firmware for these routers a couple of years ago.
There are a couple of community builds you might want to look at:
https://forum.openwrt.org/t/purefusion-wrt3200acm-wrt32x-wrt1200ac-wrt1900acs-wrt1900acv1-wrt1900acv2-builds
or
https://forum.openwrt.org/t/divested-wrt-no-nonsense-hardened-builds-for-linksys-wrt-series And the repo at:
https://divested.dev/unofficial-openwrt-builds/mvebu-linksys/
I have used Divested and I can vouch for it. It’s solid.
I have not used Purefusion so can only comment that it was an active forum.