New router tanked my internet speeds

Okay so for the last 6 months, my internet speeds have been dropping on all devices and especially on my pc. Like games that would take an hour to download, were taking double the time.

I checked the drivers, asked my isp and no issues were found so I got a new router last month.

The new router tanked my speeds immediately and after a month of trying, nothing works.

Old router was a Netgear Nighthawk R6900v2

New router is a Netgear Nighthawk RS200

Right now when only two people are actively using the internet these are the speeds given:

Nighthawk phone app test: 700.21 mbps download/ 50.3 upload
Google phone test: 428.1 Mbps download / 50.3 mbps upload
Google PC test: 3.75 mbps download / 7.52 mbps upload

When it is busy, it is far lower and my pc speeds drop to zero completely and is unable to even pull up the google speed test.

The pc ran slowly on the old router, it barely runs at all on the new one. And despite what the phone speeds say, it constantly drops when more than three people are on the phone at the same time.

Also the old router gave two separate networks, one that was 2.5g and another that was 5g. The new one only has one yet says that the phones are connected to a 2.5g network and the pc is connected to a 5g network.

Should I find a new router? Is this a common issue with this and other Netgear products? Any advice?