FIX that solve the slow/intermittent Wi-Fi connection problem of the
Realtek 8812BU Wireless LAN 802.11ac USB NIC
that worked for me...
If you have a Bluetooth USB close of your Wi-Fi USB
SEPARATE THEM !!!
You are welcome.
It was so intermittent my problem that was hard to detect.
Try to deactivate the Bluetooth and verify first. But once I separate them
the problem was solved for me.
Hope help you... let me a like if that help you. Thanks.