Interesting. When I upgraded from WiFi 5 to WiFi 6 it was a significant upgrade but there are a ton of other factors that play into what actual speeds a user may get.
I was more just interested in getting more details about OPs needs as OP basically only provided a budget, which makes it a bit difficult to give advice.
For the past 5ish years I had google WiFi pucks (gen 1, ac1200). 4 pucks, one as the router 3 as APs. 3/4 pucks were wired.
Switched over to using a NanoPi R4S (4GB version) as my router and 2x ZyXEL NWA50AX Pros for my APs. The cost for this is actually right around OPs budget, maybe a bit over.
The biggest improvements, in terms of speed for me, are devices that are WiFi 6 capable now getting much better wireless speeds (not super surprising), some going from around 200mbps to about 600mbps.
To be clear there there are over 30 devices on my network spread over 2000 sqft so I am a bit reluctant to reduce everything to a couple of speed tests when there are other factors involved.