How to properly manage my private key (pre-all forks) to get ALL future forks?

Hello i had a BTC in cold storage (not paper wallet) on electrum wallet (mnemonic seed generation) before, during and after the fork of bitcoin cash few months ago... (all in one adress/one private key)

Until recently i didnt touch anything, didnt touch BTC, didnt extract my BCH or any other fork of bitcoin.

Now i transfered a bit BTC to an exchange.

I wanna "bullet proofly" and safely store my BTC to be able to extract BCH and ANY OTHER FUTURE FORKs of bitcoin... (i didnt extract any fork yet).

My question is simple - should I move my BTC to another private key (private key "B"). Use the (now empty) original (pre fork) private key (private key "A") - to import it to some BCH wallet (Electron Cash) and extract my BCH... to some BCH private key (private key "C") COrrect?

My question is - what private key should i use in any other future fork of bitcoin? The original all-pre-forks "A" private key...? WOnt it be compromised somehow when i use it for extraction of BCH ...? Wont it compromise extraction of future forks somehow?

Or can i use the one original "A" (pre-all-forks) private key to claim any other future (or current) fork of bitcoin?