Original Setup (located at living room at ground flr)
ISP: Maxis Home Fibre 1Gbps
Existing Router: Kaonmedia AR2140 Wifi 6 router (provided by Maxis)
Modem: Skyworth with 2.5Gbe (provided by TM Unifi as backend infra)

New Setup (located at living room at ground flr)
New Router: Deco BE85  
Firmware Version: V1.0.17 Build 20240312 Rel 52632

House Dimension

Ground Floor (12xx sqft)
Upper Floor (12xx sqft)
Total sqft less than 2500 sqft)

Replace Maxis router to Deco BE85 lately, the new connectivity as below:-
Fibre services -> Skyworth Modem via 2.5Gbe port -> cat 6 cable -> BE85 10Gbps ethernet combo port

However got few issues below:
1) Abnormal WAN Port Speed Message during and after the setup, but internet is working. Tested on all the Deco ethernet ports, still the same.
2) Deco Speed Test is not working, but using other speed test tool is fine
3) Speed Test within 5 feets from BE85, Download 7xxMbps Upload 5xxMbps.
4) Speed Test from upper floor bedroom, Download 2Mbps Upload 0.xMbps (this is very bad and worst than original setup with Download 8xMbps Upload 2xMbps)

Initial expectation for BE85 which just bought this week can help provide more stable and stronger wifi coverage especially on upper floor, but now it is not the case after setup. Is there something can be fixed or product issues? Please help to advise. Thanks.