

Definitely weird. WiFi connections are poor, but VPN connection over the same WiFi link is good.
That makes me think perhaps DNS like others have said, or it could be something with your local routing table trying to reach something that’s not reachable. I would probably check the routing table first for anything weird. Like, you might have a static route applied from DHCP, but it’s ignored by your phone OS.
Since you can reproduce it in the browser I would probably look next at browser dev tools (F12). Go to the network tab. Then reproduce the problem. Once the task properly finishes, hit pause and sort by duration. You can also right click the headers and add a Timings>Latency column. See if there’s anything interesting.
Like, are the slow steps hitting a new domain name? Is there a slow POST among faster GETs? Is a step repeating after a timeout?
If nothing’s obvious there I would be tempted to repeat but lower level with wireshark to get the whole network picture. Get a good capture of the problem with a general sense of the timing of the problem pauses (in seconds from the start of capture). Find them in the cap and see what’s what. Compare good vs bad if no clear trends present themselves.




The router you need depends on your connection bandwidth and whether it uses pppoe. Also what worth considering: Do you want the router to host any VPN tunnels? Do you want some headroom for the future?
The hEX Refresh test results show that it could handle maybe 600 to maybe 800Mbps, depending on the traffic and configuration (looking at somewhere between the 512 and 1518 byte result for mixed traffic routing). It will do less with pppoe overhead. And less still if it’s hosting one end of a tunnel. But the price is good. Honestly I don’t think it would be overkill for most connections.
For me I would probably also consider the hAP ax S at this performance level. A little bit more money, but with wifi.
If you want more performance the hAP ax2 is the next step up for not much more money. It will handle gigabit fiber without a problem and also has wifi. But unlike the other two it has no USB port, so you won’t be able to expand the storage, if that is important to you.