I have an r6260 running dd-wrt which my pixel 7 was having trouble connecting to. It would connect-ish and then say there was no internet and disconnect.
It would do this more aggressively on the 5g channel than the 2.4g channel, both didn't really work well though.
Reading the syslogs in dd-wrt in the status tab logs it would show:
deauthenticated due to inactivity (timer DEAUTH/REMOVE)
A miniscule bit of a Googling led me to this post which recommended a dissoc setting that allegedly was aggressively disconnecting the client after inactivity. Switching that didn't do anything seemingly.
Another post that I saw for IOT devices recommended simplify the wireless security settings. So I went into the wireless settings tab and changed my 5g network to only support WPA2-Personal (removing WPA3-Personal) and only supporting CCMP-128 algorithms.
Save settings, reboot and voila the connection is stable. Seems like a bug in android not being very stable in mixed WPA2/WPA3 networks? Other devices like my macbook work just fine.
