As per our chat with OP, we're not blaming his router or PC - we asked that every part of the chain be investigated, which OP refuses to do. The issue here is quite simple and the facts are being mis-represented by OP to a large extent:
1. OP complained about Gaming "LAG"
2. It was established LAG exists for him including significant rubber banding in game, even though his PC reports 0-0.008% loss. For local games, this should be insignificant. This kind of rubber banding is usually the result of packet processing issues, not a ISP issue.
3. We've actively engaged OP in a 11 page private chat, running various tests, and getting results that point to packet processing issues (packet out of order - though this should not be a major issue seeing as games are UDP). Ironically these PCAP results are obtained from OP's router. No PCAP results are possible without the router as these interfere with gameplay. So yes, we have reason to want to test another router, even if the client connected directly to the ONT. Router network stacks and windows PC network stacks are very different.
4. We have not once "blamed" OP's router or PC. The fact is, OP is the only user on our network experiencing this issue. We hand over to Openserve at an NNI, and multiple other FNOs in a similar manner. Our network won't "LAG" one user and leave everyone else alone. So at this point, while we go through the motion of eliminating everything, SOP would be to also investigate the client's local hardware - especially if the issue is specific to OP.
5. We provided OP with credentials for two other ISPs, the issue, according to him, existed on those ISP networks too
6. OP obtained credentials for two other ISPs, according to OP those were clear - so that's 3 ISPs with the issue, 3 ISPs without.
7. It's. clear there's something weird going on, we have been engaging Openserve for more feedback, which is slow and not really forthcoming. Openserve's Centurion network is known to have odd niggles.
8. OP's issue is fairly unique. We've given OP the opportunity to try a test router which will 1) give us more insight into his line from his side (at the moment we're blind to his side of the line) and 2) just assist further with our investigation.