As a matter of fact, all Blockchain protocols tend to solve the consensus problem. However, the approach taken to solve this problem is where blockchain protocols are different decisively.
Blockchain protocols use several techniques such as Proof of Work, variants of byzantine fault-tolerant algorithm and strategies like PBFT and SBFT, PAXOS derivative strategies, Proof of Elapsed Time, and pluggable consensus implementations to solve the consensus problem. The primary difference between blockchain protocols lies in the way they achieve consensus.
There are other ways in which blockchain protocols can be different. One such aspect is the approach they take to implement confidentiality for executing data and transactions. Blockchain protocols including Hyperledger Fabric, Hyperledger Sawtooth Lake, Corda, and Ethereum enable comprehensive smart contracts while other protocols are quite restrictive when it comes to enabling the feature set of smart contracts.
On top of that, some blockchain protocols are general in nature and some are dedicated to specific use-cases. Blockchain protocols may also vary in terms of the type of blockchain on which they are to be implemented. For example, blockchain protocols for private permissioned blockchain may be completely different for the protocols that are implemented on a permissionless public blockchain.
So, choosing a blockchain protocol solely depends on the use-case.