Comment 2 for bug 1922715

Has exactly the same model (Dell Inspiron 24 5000 All-in-one, aka Inspiron 5400 All-in-one). Also "aplay -l" showed the card is "ALC274 Analog". Finally got the sound working in Ubuntu 20.04, by appending the following line

    𝚘𝚙𝚝𝚒𝚘𝚗𝚜 𝚜𝚗𝚍-𝚑𝚍𝚊-𝚒𝚗𝚝𝚎𝚕 𝚖𝚘𝚍𝚎𝚕=𝚍𝚎𝚕𝚕-𝚑𝚎𝚊𝚍𝚜𝚎𝚝-𝚖𝚞𝚕𝚝𝚒

in /etc/modprobe.d/alsa.conf. After reboot, the sound at both speaker and microphone worked.

Various articles mentioned this. One such reference is:
    https://bbs.archlinux.org/viewtopic.php?id=234965

A big thank you to the community!