I find myself having to choose between praying Isha at the masjid 15 min away from my house or seeking ilm. If I was not able to seek ilm before Isha that day, which one would be more beneficial? I feel a void in my heart if I do not go to the masjid and it is hard to combine both. Can't hear athan

Ustadh AbdulAziz al-Haqqan

If you cannot hear the adhan without speakers, going to the masjid is not obligatory on you, so seeking ilm that night is not a sin. Generally speaking, some scholars put seeking knowledge ahead of a deed that is not obligatory when the two clash. Of course my advice is do both.