No probs, hopefully i can help.........
I've lived in Germany for 14 years now , 4 of which as a T1. Health insurance is mandatory as you rightly state, typically your employer contributes half and you contribute the other half and is taken directly from you monthly wage. There are two types Private and Public(state) ,where private is considerably more expensive and has some benefits over Public.
I'm on the public system I and it covers my whole family. I have never had any issues with my insurer over diabetes or other medical problems (mainly leg injuries), they pay for all my insulin , test strips , needles etc etc. I'd say 90 % of doctors I have encountered speak English so language is normally not a problem. I cannot get a CGM as I have pretty good control and these are typically reserved for patients with poor control over long periods and I'm not sure if your freestyle libre would be covered here.
I can't compare it against the UK system as I have never experienced the national health wrt diabetes. One thing that is a pain here is dental , the mandatory health insurance only covers very basic dental problems , I recently had a double root canal and am awaiting the bill :-(
One other plus side is if you are T1 and on MDI , injecting > 4 times per day is you qualify for the schwerbehindertenausweis grad 50%, which is effectively stating you are disabled due to lifestyle restrictions. This has certain benefits such as 1 week extra vacation per year, tax breaks, no overtime/on call (unless you specifically insist on doing it) and bizarrely it can even get discount on new cars in some cases 30 % off.
Let me know if have any specific questions , where in Germany will you be residing ?