They're is so much wrong here I don't know where to start.
-
get a better wifi 6ap. You should be getting about 2x the bandwidth. I get about 900mbps on my 5 year old cell phone sitting on the couch.
-
Wi-Fi 7 smaller width channels to avoid interference. Pretty much everything you've said here is backwards/wrong and i encourage you to do some learning on your own.
The lite, being the cheapest model in that line, unsurprisingly only supports 2x2 mimo. Getting 600mbps from that is actually really good, but given net bandwidth is nearly identical to what is available for wifi5 I'm not surprised you didn't see much of a difference.
An ap with 4x4 mimo would substantially outpace your wifi 5 router.