Can't access home assistant via ethernet

Hi all.
I’ve a problem that I can’t solve. I’ve changed my modem/router with a newest (LTE) one: with the previous router there were no problems at all. I could access HA from the PC (wired via Ethernet cable), phones via wifi and via Internet (i.e. from work).
After I’ve changed router, I can access HA only via WiFi and via Internet.
From the PC I can ping it, I even use AdGuard as a DNS with filters, but I can’t access the login page or the dashboard. I can’t even access the files using File Explorer (in the past I could do this). If it means something, I’ve opened all the ports on the router for the raspberry with HA, but without luck.

Any help is appreciated, thank you!

Maybe router has some firewall blocking connections lan to lan

Oops: you edited. I don’t think so… there are no rules other than the ones I’ve set up for home assistant. And I can access a NAS that I have with no problems. (Nas is wired)

I’ll add some info. Installed additional components: AdGuard, Advanced SSH and terminal, DuckDNS, File Editor, Home assistant Google Drive backup, NGInx, samba share, Wireguard.