OK. I'll talk you through my own situation.
I assume you have the Miononno script that allows access to band and cell locking.
I can receive seven different masts of varying signal strength, but for all practical purposes this can be reduced to just two.
Tower 1 has b1 and b3 - this is 4g+ only
Tower 2 has b20 b3 b32 and N78 (5G)
Simply allowing auto everything it will either go to T2 and hook up to b20 or to T1 and hook up to b1 or b3. Connecting to B20, it goes to T2 and and I get 5G
But connecting to tower 1 allows cross-tower connection to T2's N78 and the NSA 1+3 gives better uploads. Even better for uploads would be if the primary band is b3.
So it is better to either band lock or cell lock to T1.
If I band connect to 1+3 there is no guarantee it will always connect to the better band of the two as the primary. Sometime it will connect to b1 first. By selecting each band in turn I can note down the cell info. Then I can use that info and key in cell lock for T1's b3 and that will force the router to always select that band first. It will then seek out any 5g aggregation. which in my case will be b1 and then N78.
Another scenario might be if I lost 5G. In that case T2 would give the better 4G+ performance with slightly slower maximum speeds but much better consistency because T1 can get overloaded. If I just did band selection of b20+3+32 the router would just jump to the strongest signal on b3 on T1 and lock out the desired b32. Doing a cell lock to T2's b20 will mean that the other bands on the same tower, b3 +b32 will get selected. (Unfortunately b32 doesn't get selected when 5G is operating.)
So in short, get that Miononno script, find out what bands are available and what their PCI and EARFCN numbers are and then play around with different combinations.
You might also get the Cellmapper app for your phone and note down the various sgnals you can find while wandering around the house.
Note, PCI numbers are different on different towers, EARFCN numbers are always the same for the same bands, e,g for Three, b20 = 6175, B3 = 1392 etc.
Hope that helps a little.