Hot spot speed on Magenta 55+

I just signed up last month for the Magenta 55+ plan.  Using Speedtest at my current location, I’m showing 459 Mbps download and 103 Mbps upload on my iPhone 14+.  Which is wonderful.  However, when I use my phone as a Hotspot to my HP computer or my Android tablet, the speed goes way down to around 25-35/25-30.  Sometimes much lower (around 5/3).  Why is this and how can I fix it?  Thanks.