Have you checked your signal strength (numeric value) ?
Open phone app
Goto the keypad and enter *3001#12345#*
Press the green dial (phone) button
From the Main Menu that opens up, press LTE, press ‘Serving Cell Meas’ and the negative value against ‘rsrp0’ is your numeric signal strength
The range for this is -50 to -120, iirc
The lower the number, the better your signal strength.. So, -105 is bad while -70 is excellent
Mine hovers between -105 to -116 inside the house...that’s pretty bad
However, it’s the same on my Note 9 (using the LTE Discovery app)..and here’s the kicker.. even with such low signal strength the Note 9 pulls way...way ahead of the XS in speedtest and practical usage ( web browsing, logging into apps like Chase, AMEX etc..) on LTE for me
WiFi speeds are very similar on both devices, per speedtest, but the Note 9 renders faster on WiFi as well!