If I'm not wrong miners are trying to find nonce that satisfies a rule.
Then why is btc so slow? I want a technical answer.
Can btc ever match eth speed, given no politics?
Most simple and foreseen reason:
Bitcoin's blocktime is set at 10 minutes, while Ethereum has a block every 10-20 seconds, making it much faster.
So no, bitcoin will probably never be able to match Ethereum's speed. ( In it's current state)
(Unless they would implement something like the lightning network.)
BTC transaction confirmation can be "slow" because of a combination of factors, including:
If you want fast confirmation, you up the fee, thereby ensuring you get prioritized by miners for inclusion in the next block.
See https://www.cryptocompare.com/coins/guides/what-is-the-block-size-limit/ for an interesting discussion about the pros and cons of the block size limit, and the effect that has on transaction processing.