I had sent it sent directly to coinbase.com exchange, because I had plans to converting it to SOL. I'll never make that mistake again.
If you had sent the fund to your own wallet and you had the private key, you would be able to do CPFP, but you had to pay a very big fee for the CPFP transaction.
The network has become less congested and around 90 sat/vbyte is required for getting confirmation now. To increase the effective fee rate of your transaction, you would have to pay around 0.025 BTC for the CPFP transaction.
Would you pay that high fee, if you could do CPFP?
Since I sent it directly to coinbase.com and they own those private keys, would it be possible that coinbase is leveraging my hash with high rate fee to get other low rate fee hashes confirmed?
Technically, it's possible that coinbase do CPFP and make your transaction confirmed, but they will never do that.