Any advice to get the block gas limit? I'm using the ethers.js library.

On our side, we do not have any limitations (inside Aurora Engine). Block gas limit exists only in the form of NEAR block gas limit. Both are not easily mapped into each other.

Near gas has an approximate relation to computing time, where 1sec corresponds to 1PGas or 10^15 Gas. 1PTgas is also what is allowed per shard per block. This is configured as gas_limit and it can be looked up through an  API call to NEAR node.

Transaction limit is set to 300 NEAR TGas.