i honestly am not so sure which scripts bitcoin core considered non-standard by default. i may be misunderstanding the c++ code of it but it seems like it could consider OP_CLV as non-standard which is weird because i have seen people make this type of transaction.
I read few articles, and it looks like that every P2PKH output will be considered as "nonstandard" if it not following standard scheme (which i linked above)
Here some explaining from Achow101:
https://bitcoin.stackexchange.com/questions/81623/non-standard-transaction-scripts-broadcastingOP_CLTV is nonstadard in P2PKH. But standard in P2SH. Ordinary locktime is standard too, but it's not an opcode, just a special field (just a number) in transaction.