fundrawtransaction, send, sendall, and walletcreatefundedpsbt all document maxconf as Optional::OMITTED, while the sibling parameter minconf explicitly documents its default of 0. The actual default for maxconf is 9999999 (DEFAULT_MAX_DEPTH in src/wallet/coincontrol.h).
listunspent already documents this correctly:
{"maxconf", RPCArg::Type::NUM, RPCArg::Default{9999999}, "The maximum confirmations to filter"},
This PR applies the same pattern to the four affected RPCs for consistency.