scaling is not just about making the blocks bigger, that would be the easiest and least efficient solution. scaling is about increasing the efficiency so the same space could be used better. for example the new Schnorr signature proposal alongside Musig would use the same space but can shrink the transaction size by a lot, hence increasing "capacity" which you can refer to as scaling bitcoin.
speaking of efficiency i think we can categorize Erlay under scaling:
https://bitcoinops.org/en/newsletters/2019/06/05/- Sharding
And just straight up Blockchain Pruning, where nodes don't have to store the entire blockchain is another..
sharding and pruning both are not scaling solutions, they are ways that can make it easier for individuals to run a full node since they reduce the storage space requirement.
categorizing them as scaling solutions is like saying running an SPV node is a scaling solution!