T-Mobile Home Internet: Best Antenna for B525s Router, LTE Bands 1800+800mhz, 800mhz, 800+2600mhz

Hello, I'll start with the fact that I'm new here and if I wrote in the wrong section, please correct it.
Well, I took the above-mentioned internet for tests with the option of up to 20 mb / s (in the living room they told me that 60mbs does not make sense because the transmitters are overloaded in my location, but you can always change) the B525s router. At night I was getting over 20mb / s DL, but the Up is low because max 6mb / s.
I forced all LTE bands and the best was 1800 + 800mhz, 800mhz and 800 + 2600, below I will add photos from tests and the app.
1800 + 800


800


800 + 2600


And my question is, why is it connected to the transmitter from Żeromski in the middle of the city through which I have 2.85 km in a straight line, and not to another which is closer (there are probably 4 of them)?
My location is: Radom, ul. Skaryszewska 80-90 (does not give the exact house number for private reasons)

In addition, I have a higher download speed on steam than on speedtests:


What antenna to buy for this?
When I put the router out of the window of a one-story house, I suddenly have 4 LTE lines, and usually there are 2/3 inside the house on the same window sill.
Thank you in advance for your help!

Force the LTE1800 and the LTE2600 itself. These three measurements showed association with or aggregation with LTE800 as baseband. Signal at home is weak. Do the tests outside the window, also with the LTE800 itself.

I have already done tests on the window:
1800:

1800 + 2600:

2600:

800:

LTE1800 and LTE1800 + 2600 from Słowacki 257, poorly clogged BTS. LTE800 from Wrocławska 3, also linden. The only chance, as you can see, is Żeromski. generally, it can be seen that in Radom, t-mobile has problems with speeds on LTE.

Does it make sense to buy an antenna? If so, what? 150 PLN budget but it can be a bit more.

The parameters of the signal from Żeromski are very weak, especially in the higher bands, and this is one of the LTE2600 from Słowacki 102 (eNB 187016). Antenna necessary.

What antenna model so that I would not buy a sell

The question is, do you want to use LTE2600, LTE1800 or LTE800? Because the result on LTE800 from Żeromski was good. Although the 3 o'clock test is unreliable.

Well, I don't know, there are antennas from the 800 to 2600 band so that you can change the range and get the best result?
I will add that I have a steel pipe installed on the roof from the old internet, which is about a meter and a half.

There are broadband antennas but they have lower gain and wider beam angles.

The 1800 + 2600 band from the Slovak 257 is definitely winning, I tested outside the window and at 22 m and it came out 18downl and 20up (LTE 4 lines), so I will buy the 1800-2600 band. Do you recommend a specific model?

At 1800-2600MHz http://www.cybertech.com.pl/p173,antena-dualna-lte-a-4g-17dbi-mimo-1800-2600mhz.html, cable maximum 10m and SMA connector on the cable.

thanks for the help