Low bandwidth troubleshooting

Bloody noob here, I need high-level information on where to start troubleshooting the following:

I installed Win11 using the Ubuntu tutorial. Everything seems to work, but I get very low internet speeds. I get results using search engines and can visit some ‘simple’ sites, but most web pages fail to load. Download speeds are in the tens of kb/s.

Please let me know where to ask next or which additional information you need.