Cheapest laptop I can buy if I am only concerned with remote exploits?

Hi.

I need to buy a laptop that is cheap (up to £500).

I am not concerned with physical attacks: I won’t carry it with me anywhere, and will always keep it safe, and there won’t be any sensitive data in it stored.

However, I have seen some here say that firmware updates such as CPU microcodes are essential, because the lack of these updates can facilitate remote exploits (e.g. Xen exploits)?

If that is the case, what is the minimum I need to watch out for if my only concern are remote attacks?

Is a Thinkpad T480 bad?

Thanks