Why not get a $5/mo VPS and use VPN?
If your ISP is tampering with packets, that is the anti-pattern that needs to be remediated ASAP.
In my opinion, the only packet change behavior that an ISP should be involved in is adhering to QoS headers. 0x08, it's bulk. 0x04 reliability, 0x10 low latency. And if they want to charge me more for 0x04, that is fine if it's clearly spelled out in the contract.