Are they exchanged TestNet Coins (TestNet3/TESTET4)?

I am a developer working on blockchain applications and need a ton of testnet coins (ETH, Solana, Tron, etc.) for testing. Faucets usually only offer small quantities, but not enough for large-scale testing.

I already have some Bitcoin Testnet Coins (TestNet4). Are there any exchanges or services (BTC TestNet4→ETH TestNet, or other testnet currency) that allow you to exchange TestNet coins? Or is it the only way to get a ton of Testnet Coins through a specific developer program or private faucet?