I think your limiting factor now is your router being handicapped by the WAN Gigabit.
Until you switch it out to a 2.5Gb or 10Gb capable router, it will stay at around Gigabit (when you are using the ethernet cable hooked up to your laptop.
Make sure your router & the expensive adapter is 10Gb capable if you're looking to shred that speed with the allocated bandwidth.
WiFi test on the other hand, I recommend getting a router that is WiFi 7 and with a minimum 2.5Gbps WAN port capable if you want to utilize the bandwidth you got. The TP-Link Archer's BE series seems to tick those boxes with its I/O.
I can't find any other USB-C 10Gbps Adapter other than the OWC Thunderbolt 10G Ethernet Adapter, so hopefully that adapter you got is actually Gigabit at minimum.
Hey! Thanks for replying!
I have not thrown the static IPv4 yet onto
our plan (it's my parents lol) as my NAS plan is still WIP and I'm commissioning it only next month.
So summarizing, I cannot get a static IP from SIMBA
yet (because CGNAT and no IPv4 availability) which means I am not going to be able to remotely access my server from the rolling IP address and combining with Tailscale VPN etc.
I definitely am a fan for the cheap-ness for that bandwidth, but I'll hold out until they allow static IPv4- then I'll probably get this plan for myself to enjoy.

Sadly MyRepublic also released this 3Gbps plan just 2 months after my family signed the re-contract and we cannot upgrade to enjoy this new speed for literally +$1.00, and pleading with the clueless foreign web support agent didn't get me / anyone else (from reddit threads) anywhere which absolutely sucks.
Looks like I'm gonna stick with ye' ol' 1 Gigabit for another 22 more months, or observe and YOLO my chances with SIMBA.
p.s. SIMBA currently only services 2.5Gbps to my area. 10Gbps only in certain areas.
Pulled from SIMBA FAQ -
"SIMBA 10Gbps Broadband is available to select residential addresses in:
East: Bedok, Eastwood, Eunos, Geylang, Macpherson, Joo Chiat, Katong, Kew Drive, and Upper East Coast
North: Admiralty, Sembawang, Woodlands and Yishun
North-East: Ang Mo Kio, Hougang, Punggol, Seletar, Sengkang and Serangoon Gardens
North-West: Bukit Panjang and Choa Chu Kang
"