@Joseph-TP Hi, I would also like to chime in on this same issue. My plan is rated 100Mbps for both Upload and Download. The Download speeds get throttled down to 44.3- 51.0Mbps but Upload speeds have remained unaffected, getting between 114-128Mbps. I have read the suggested fix for this issue but in some cases, including mine, the ISP doesn't play nice and only binds their ONT's WAN MAC for authentication so WAN MAC Cloning becomes a necessary tool.
I hope TP-Link releases a firmware update addressing this issue as soon as possible.

• Running - 
  • Firmware Version: 0.7.0 3.0.0 v6096.0 Build 250606 Rel.25672n
  • Hardware Version: XX530v v1.0 00000001
     

I am facing same issue. I am on Excitel broadband. Default onu gives 200mbps but my new xx530v. Only gives 45-50mbps. Also there are not firmware downloads available for this router. So no way to downgrade either. 

  @shu006 I am on Tachyon Broadband . I had 0.4.0 out of the box but the router was showing LOS (red blinking light). Later I figured that, that version only supported GPON and they were on EPON. I upgraded to 0.6.0. It worked and internet was on. Running a speedtests on 0.6.0 and 0.7.0, both had the same issue.

You can probably do the below if Excitel cooperates-

Turn off router > disconnect the Fiber line > ask Excitel to unbind the old MAC > turn on the router then choose the 'Do not Clone MAC' in the WAN > reconnect the fiber. 

(Don't turn on router with fiber connected while doing so because the router will again send the old MAC & will get binded again.)

I sent an email to my ISP asking for my credentials for PPPoE and any other information I may need to setup my own ONT but they straight up declined saying quote-

Our network and systems are designed to work with the ONTs that we supply, as they run on our customized firmware.

This enables us to monitor connection vitals, ensure stability, and provide timely troubleshooting.

If an external ONT is used in place of the provided device, our system will not be able to recognize or support it. In such cases, we will not be able to assist you with most service issues, diagnostics, or fault resolution.

We sincerely regret that we cannot fulfill this request.

But I still managed to scrape together information to set it up and internet works. LOL. I'll still ask my local technician if he can unbind the MAC in a few days. Hopefully this will resolve it. 

I have already sent an email to TP-Link India regarding this issue and attached this and one more thread from this forum. 

I can share the firmware files if you need. 

  @Yash_Kanawjia can you provide 0.4 and 0.5 firemware files? 

  @shu006 I don't have the 0.4.0 firmware as it is what came out of the box and there was no way to download and I'm sorry I mistook another file for being 0.5.0, never had 0.5.0. The 2 files I have are of 0.6.0 and 0.7.0-
XX530v Firmware Files
I'll see if I can get 0.4.0 from somewhere.

(Note: Updated my above message about having 0.5.0. Removed its references from the message #24)