1. Why is BTC fee high?
It's a free market, and the highest bidder wins.
2. How do I circumvent high fees?
Don't collect small Bitcoin inputs, use Segwit, and if possible use LN.
3. Why aren't developers tweaking the Bitcoin blockchain code to accommodate millions of transaction like Solana and BNB?
I don't know Solana but BNB is a centralized shitcoin made up by a rich guy. A centralized database can't be compared to a decentralized blockchain.
4. How Can I Pay Lower Bitcoin Transaction Fee and Not Get Stuck?
You can't.