If you use uboot, pls make sure the router goes to uboot mode.
Also show a screenshot of your browser, with the address bar. Maybe the browser address is modified. Probably because you use clean openwrt with luci before.
Clear browser cache or use a private browser tab may solve this.
I’m sure the router is in uboot mode and the network address have been set.
Even though I cleared the browser cache, I couldn’t access the http://192.168.1.1
See the picture below.
Pls fill the gateway 192.168.1.1. This is not necessary but does not hurt to fill.
Pls check your browser if it is redirected to https. It should keep http.
Make sure the cable is inserted before powering on the router.
If all the above is done but still cannot access uboot. Consider changing on pc or use an Ethernet switch in the middle. Such situation happened before, but rarely.