The term blockchain trilemma is familiar to enthusiasts in this industry, its components are security, decentralization & scalability. Of the three components, Bitcoin (BTC) is weak in scalability, with a maximum of 7 transactions per second. I know we have scaling solutions like LN now, but I'm talking about the core infrastructure here. Seeing Bitcoin (BTC) is weak in terms of scalability, maybe I'll create a coin with high scalability, faster than Solana (SOL) with their PoH.
This is the first thing I thought of. Whenever there are too many transactions, there is congestion, and that will lead to higher fees and longer times for transactions to be confirmed. I think this is one of the major flaws in Bitcoin. If bitcoin is used more as a currency, that will mean many more transactions will be done a day, and with the adoption of bitcoin increasing, this can be a problem.
I don't know anything about developing Bitcoin or cryptography, but another thing I would like, if I had a coin, would be to try and make the average confirmation time lower. Ten minutes isn't a lot of time, but as a currency, it will mean a lot if you pay for something in a store with bitcoin and you have to wait for the transaction to confirm before you leave the store. A maximum of 2-5 minutes to confirm a transaction won't be bad.