With the iancoleman.io/bip39 script I was able to recreate Electrum wallet addresses with the zprv... key from Electrum console getmasterprivate() in the form's field "BIP32 Root Key", selected Derivation Path tab "BIP141" with m/0 for receive addresses or m/1 for change addresses in field "BIP32 Derivation Path" and P2WPKH in field "Script Semantics" for native segwit addresses.
Yes, this is correct. This takes the extended key from Electrum, which is already at m/0', and derives at /0/0 (or /1/0 for change) to reach the same addresses Electrum generates.
I want to test a recovery in some other suitable wallet, maybe Sparrow or some other that supports to import a x/y/zprv master private key.
This is where things get confusing, partly because of the terminology used and partly because of BIP39 and Electrum following different standard derivation paths. Technically speaking, master keys are the keys at m (or M for public keys). Any child key at a level below that which contains the chain code necessary for generation of further child keys is an extended key, but Electrum calls the extended keys at m/0' the master keys. Some BIP39 wallets will call the keys at m the master keys, while others will call the keys at m/84'/0'/0' (for segwit) the master keys. Importing a zprv derived at one level in to a wallet which treats it as from a different level can result in different addresses being generated.
Better to just stick with seed phrases.