You will need to bite the bullet and buy a new Mac. Apple silicon Macs really beat the pants off the old Intel ones - you can get very good machines of M2 and upwards Apple silicon. A new one today should last you 10 years +
Having said that, consider repurposing your old MBA for another purpose. I have a 2011 MBA that’s only purpose is to run a Drobo disc array in a cupboard as local backup. With the door shut, I can’t hear the whine of the disc drives/fan of the Drobo (now obsolete)
Remember, you cannot have too many backups of your data