Yea it does look like 5 year old M1's are going for $300 on eBay, but man that's painful a 5 year old machine for that much when you could get a new Neo or Mini for $600, if only you could buy them. I probably should just get the M1, test and sell it back on eBay. Thanks.
They are similarly good. In fact I prefer my M1 MBA to the newer models because of its shape.
If a $300 Mac can do the job, a $600 Mac is overkill.
If you literally just need to borrow one, I'd just buy an Air from Apple directly and then return it within the 14 day window. I'll sometimes do this if I need an extended repair on my personal one, or there's a new mac I want to try.
If you're going to do any kind of work on it I'd choose a 5-year old 16 GB memory M1 over a Neo every single time. 8 GB is what's painful. The CPU difference is very small anyway.