After choosing DHCP on the OpenWRT firmware, TP-link stopped responding and 192.168.1.1 does not respond either. How to return?

Question

DHCP

The problem is very similar to After choosing DHCP on a freshly installed OpenWRT firmware, the router stopped responding and 192.168.1.1 does not respond either. How to return? , however, the user decided not to advertise how he solved it.
So, there is a TL-WR841N router, its WAN port burned out, I reflashed it to OpenWRT (I don’t remember exactly which version, it was about 2 years ago). All this time it worked properly and received the Internet in the first LAN port (reconfigured) and distributed Wi-Fi. I needed to change the static IP to DHCP on the 1st LAN port (which is now WAN), after rebooting TP-LINK stopped distributing DHCP, when I tried to enter IP manually (192.168.1.1 gateway, my ip is 192.168.1.2, the same with the second subnet) . At the same time, it seems that the router is still working, only I cannot get into its network.
I can connect via Wi-FI using the old SSID and password, but the IP is not given to me, again, when I try to enter it manually, nothing happens, I just don’t see the router.
I also can’t log in via TElnet, if I turn off the router, press the reset button and turn it on, the sys lamp starts blinking quickly, while I still can’t connect via telnet (I try to connect to different IPs) All kinds of network scanners do not find anything.
//upd
By the way, I tried to raise a DHCP server on Windows (I don’t know if it was possible or not) and distribute IP on that first port, but apparently this didn’t work, or it doesn’t work that way.
//upd2 I have a ch341a programmer, what if I flash the flash drive directly through it and try to start? Will it work?
//upd3 somehow (turned on with the reset key pressed) managed to start some mode when the power diode and the "lock" are on. In this mode, I receive exactly 85 packets after a certain period of time, while setting the subnet to 192.168.0.1/24 . 0.1 still does not see. Before that, I did not receive packages at all.