It's very interesting question. Aside from fee rate, miner also need to ensure that total sigops cost of the block isn't above 80000[1]. Otherwise, they may accidentally create invalid block which happened to F2Pool on last year[2].

[1] https://github.com/bitcoin/bitcoin/blob/v27.1/src/consensus/consensus.h#L16-L17
[2] https://bitcoin.stackexchange.com/q/117837