Can I make a resolutive condition or suspensive condition?

This depends on whether it is an foreclosure auction, bankruptcy auction or public auction.

Foreclosure auction: Unconditional purchases are always made at the foreclosure auction. The reservations that are customary with a private sale, such as obtaining sufficient financing or a housing permit, are not possible at auction. So make sure that there is sufficient certainty in advance about getting the required mortgage and any permits.

Banktruptcy auction: The bankruptcy auction often proceeds unconditionally, without reservations that are customary with a private sale, such as for obtaining sufficient financing or a housing permit. This also differs per auction and can be found in the draft purchase contract.

Public auction: At a public auction, property is often bought unconditionally and sometimes with reservations that are customary with a private sale, such as for obtaining sufficient financing or a housing permit. What is applicable differs per auction and can be found in the draft purchase contract.