Is there any ways to improve the speed? The answer is YES. I did it. I downloaded and installed the RASPPPOE and used the TCP Optimizer with these config: Apply for Streamyx 1Mbps package.

General Settings tab:
Custom settings - check
Modify All Network Adapters - check
network adapter selection - your NIC
MTU 1492
TTL - 64
TCP Receive Window -63888
MTU Discovery - Yes
Black Hole Detect - No
Selective Acks - Yes
Max Duplicate ACKs - 2
TCP 1323 Options:
Windows Scaling - uncheck
Timestamps - uncheck
Advanced Settings tab:
Max Connections per Server - 10
Max Connections per 1.0 Server - 20
LocalPriority - 5
Host Priority - 6
DNSPriority - 7
NetbtPriority - 8
Lan Browsing speedup - optimized
QoS: NonBestEffortLimit - 0
ToS: DisableUserTOSSetting - 0
ToS: DefaultTOSValue - 240
MaxNegativeCacheTtl - 0
NetFailureCacheTime - 0
NegativeSOACache Time - 0
LAN Request Buffer Size - 32768
Then select "Apply Changes" and reboot to take effect

My download speed increased from below 100KBps to 110KBps. Tested by using the streamyx bandwidth test.

You guys can try it and hopefully you all can improve y'all speed.