Poor 5G + Performance

[ArronCW7]

I have noticed quite alot over the last few months 5G speeds have dropped quite alot in my area. 5G+ was turned on in August in my town i have a 5G SA signal on my phone as confirmed through the signal screen accessed through the Apple Keypad & nPerf. I used to get a balmy 150mbps on NSA now i struggle to get above 40mbps with regular drop outs of mobile data on SA (speeds drop to about 500kbps for around 5 mins) Its not a device issue as its happening on my iPhone 16 Pro, my work iPhone 15 & my partners Pixel 10 Pro. The mast that serves my house is a large 45m MBNL one so it is shared with Three & now i know Vodafone are looking to use it for 5G through the MOCN (friend works for vodafone) I do fear that once vodafone have customers using the same cell site its speeds & reliability will drop even further. I have reported this through the App multiple times & every time i get told ‘no fault found’ can this be looked into properly ? Surely there is a fault or overloading when speeds are slow & the mast is quite obviously crashing causing the periods of it being unusable. 
Thanks

[bristolian]

There's some misunderstanding regarding how site sharing works.

It sounds like multiple operators may be sharing the same structure, but they will all have separate & independent equipment there. The MOCN arrangement that VF & 3 are using is unique to their specific situation.

The MBNL share only had common active equipment for 3G, which has been long since decomissioned. For subsequent radio technologies, passive components such as tower structures may be common, but all active equipment is completely separate.

It's entirely feasible that VF using MOCN will impact 3's speeds from this site, but EE's equipment will be entirely separate from theirs.

[ArronCW7]

I know this mast has a single fibre feeding it which powers both EE & Three all Microwave transmission was cut & dishes taken down about 18 months ago. It could be a matter that the fibre feeding it is being throttled or has contention issues. Like i said the mast is 45m in a relatively flat area so devices further away could be tracking to it. It could be one of many things but to me its got to be either congestion or the physical transmission to it. 

[bristolian]

There may be one single physical fibre backhaul, but individual spectrum within that feed can be separated.

I can assure you, EE & 3 do not share any active radio equipment on 2G, 4G or 5G