Want reassurance: does brake fluid look like just had an "exchange" or "flush" at dealer?

I'm looking for reassurnce I don't need to go back and deal with this dealership service dept. again. But based on cumulative minor past experiences I have some misgivings about the service dept. at the Toyota dealer where I bought my Gen 4 Toyota Prius LE-AWD. I have used them in past for the free servicings under ToyotaCare and yesterday went and paid for 30,000 mile servicing and because I didn't have my wits about me due to barely being recovered from a 3 week long bout with COVID I agreed to a "brake fluid flush" or "brake fluid exchange" before doing my research. I might not have done it if I had but it's done now -- except I'm paranoid maybe it wasn't but they charged me anyway?

1. My first concern was that most of the areas under the hood looked maybe air blasted clean except on top of the brake fluid reservoir (although tray above it, it's kinda recessed on this model, does look fairly clean). It's possible they blasted the dust back there though after doing the exchange so who knows. Also when they do this do they use the cap on top of reservoir or is there another access point?
   
   
2. I also got concerned because level of brake fluid was at same place as before which was 2/3 way roughly between min and max near a different line there -- but based on online research this is a "Support line" and is where it should be, correct? On phone later dealer service person sort of confirmed this but not clear they knew what they were talking about.
   
   
3. I opened the cap to look at the brake fluid in the reservoir. This is okay, right? I read online it was despite the "pressurized" warnings.
   
   
4. I looked inside and it's a sort of partly translucent partly yellow cloudy goop. There may be dark areas of it but I'm pretty sure I'm seeing through to what's below it. There might have been a little gray gunk line at edge of fluid by plastic but slightly hard to tell and didn't photograph well.
   
   
5. Can I stop worrying about this and assume it was done or if it wasn't impossible to prove one way or another and I'm just out the money and move on because it was probably unnecessary anyway and this all looks fine, or should I do something further here? If you're going to say test it, which test do you trust and anyway do you think the dealer will accept that result as proof?
   

 

Thank you so much Doug for all this reassuring and helpful advice and yeah the car is 3 years old as despite being 2022 model we bought it in August 2021, so maybe good thing. Anyway, thanks again!