Some comments from @sipa in #12702.

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Yes, I think `importmulti` is superior in every way, except:
* Slightly less convenient to use (it requires redundant information, as you have to explicitly state what you want to import, and then give the keys/... to enable that).
* ~Doesn't support P2SH-P2WPKH yet~. Added in #14454

The latter can be fixed by just adding support for that case. The former can be improved by adding 'default' cases (e.g. if you prove a WIF private key, it can permit omitting the address, ...).

const CTransaction txConst(*psbtx.tx);
    
    bool bip32derivs = request.params[4].isNull() ? false : request.params[4].get_bool();
    FillPSBT(pwallet, psbtx, &txConst, 1, false, bip32derivs);
    
    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
    ssTx << psbtx;
    UniValue result(UniValue::VOBJ);
    result.pushKV("psbt", EncodeBase64((unsigned char*)ssTx.data(), ssTx.size()));
    result.pushKV("fee", ValueFromAmount(fee));
    result.pushKV("changepos", change_position);
    return result;
}
UniValue abortrescan(const JSONRPCRequest& request); 
UniValue dumpprivkey(const JSONRPCRequest& request); 
UniValue importprivkey(const JSONRPCRequest& request);
UniValue importaddress(const JSONRPCRequest& request);
UniValue importpubkey(const JSONRPCRequest& request);
UniValue dumpwallet(const JSONRPCRequest& request);
UniValue importwallet(const JSONRPCRequest& request);
UniValue importprunedfunds(const JSONRPCRequest& request);
UniValue removeprunedfunds(const JSONRPCRequest& request);
UniValue importmulti(const JSONRPCRequest& request);
static const CRPCCommand commands[] =
{ 
    
    { "generating",         "generate",                         &generate,                      {"nblocks","maxtries"} },
    { "hidden",             "addwitnessaddress",                &addwitnessaddress,             {"address","p2sh"} },
    { "hidden",             "resendwallettransactions",         &resendwallettransactions,      {} },