Answer for what option is best in Electrum

The answer is for that topic: https://ccfound.com/en/questions/6019/amongst-3-fee-rate-options-in-electrum-wallet-what-do-you-prefer-and-should-use

What option to choose actually depends on your need. It's hard to say what option is the best.

Here, I only want to point out that if you need to pick a default option & less regularly check its estimation, recommended fee then compare (double check) with mempool websites, the best option in Electrum is:
Mempool.

See the screenshots, for three options, at almost the same time. You see two other options, ETA (Estimate Time of Arrival) and Static, give you overpaid-estimated fees. Mempool is the best but it is not perfect and still be overpaid. If you want the best, no other ways than checking mempools by yourself.

Note: I tested it with three options and given estimated fees for next 10 blocks (10 vMB from tip of mempool).