Why can't we mine our own transactions?

Is there a reason we can’t mine our own transactions? not the full , but a portion so we’d pay less fees and use our own hardware power when needed to take strain off the networks? would be an awesome way to take some of this stress off the network. even if it just helped 1%. I was waiting for my transaction to go through today and it took over an hour and I missed a buying opportunity on a product as i waited for the funds to get to the wallet I needed it in. If there was a radio button or checkbox to allow my computer to mine a portion of the transaction, couldn’t this help in more ways than one?

Transactions are not mined, blocks are - and they include transactions in them. Anyone can qualify to be a block producer by running a pool. Users do not (and should not) have any control on who creates which block - the schedule is created based on pool’s keys and no one other than the pool operator himself would know the schedule.

Transactions on blockchain take on average 20 seconds. If you’re referring to a transaction from exchange, please note that exchanges queue up and delay transactions submitting them in batch. That delay has got nothing to do with any blockchain.

this applies to both proof of stake and work? so all of the delay is mainly coming from the exchanges in both cases due to how they process the transactions?

Until get the final transaction ID that you can query on explorer, yes…