Buying advice: Macbook pro m1 pro or macbook air m2 15’’?

I would rule out any used Mac being advertised as "refurbished". Apple is the only authorized source of refurbished Macs, so the fact the seller is being disingenuous is enough for me to immediately and reflexively reject them as a potential vendor. Look elsewhere.

There is no problem buying a used Mac, but a conscientious seller will have no problem advertising it as such. They absolutely positively must comply with Apple's instructions: What to do before you sell, give away, trade in, or recycle your Mac - Apple Support. A reputable vendor will include a reasonable warranty and equally reasonable "no questions asked" return policy — just like Apple. And, if they do, you will find their prices nearly equal to those on Apple's Certified Refurbished Products page anyway.

There are exceptions. You can occasionally find "screaming good deals" on the used market, but they are rare.

I strongly recommend that you consider 512 GB as the minimum amount of storage. 16 GB RAM is fine.

How long are you planning to keep that Mac?

The reason for asking is that lots of people buy Macs without a lot of storage because they might not have the additional funds at the time, but then they wind up keeping them a lot longer than expected. Sometimes ten years or more. This forum is full of examples.

Macs last a long time. Amortized over that useful life, 230€ might be an insignificant amount of money, but one will less storage will not be viable for as long. Only you can decide.