There are so many reasons why I hate this comparison with merlin parks, but also I think it's important. Just a few reasons off the top of my head as to why the experience of availability and attraction quality varies between the parks:
1. The vast majority of rides at Europa, the owners of the park literally created and ingrained into the park to run as a show piece to sell them as units. If they're not operating correctly at its home park, who would want to buy it?
2. Culture. British culture is totally different to German culture. Entitlement. Expectations. Efficiency.
Things like breakdown information should be no different from park to park to be honest, it is a matter of an employee getting on a microphone and updating everyone, however when you have a lot more people to control, people asking you whats going on who're higher up, and things to get on with yourself, simple things like communicating with guests can simply slip your mind. The best excuse here is some parks simply do not distribute their PA systems properly and some attraction queues are speaker-less, but also priorities in these moments lay elsewhere, right or wrong.
And point 2 up there^ applies to guests and employees too. If you're told as a worker you'll close your gates at 5, you make plans. If you are then told that park opening is extended by an hour on the day, you will obviously be somewhat upset. Parks like Europa which don't set their closing time until the day don't set up this expectation for their staff.
3. This is the big one - procedures. The way Europa is ran is (i'm fairly sure) unlike most parks. From what I know each major attraction permanently has an engineer stationed at the ride, along with at least 1 team leader, and the attractions team are given a lot more responsibility than those found at other parks. Troubleshooting before there is even trouble. This means things like E-stops can be reset in a matter of seconds, rather than in comparison at merlin parks where it must be overseen by a member of rides management and/or engineer, and potentially park management. Trains can be added or taken off without you even noticing. Paperwork is much more simplified due to the procedures that take place through day to day operations, and there just seems to be more trust and freedom for employees to get on wither their job compared to the scripted out roles found at many other parks. Rather than a group of roaming engineers and park management who's responsibility lays across the park, this constant presence of relevant employees at places where they MAY be needed works much better than those who wait about until they ARE needed, and then may fall in demand if they're needed in more than 1 place at once.
4. Finally, Merlin was a floating company up until recently. Europa is family owned. The quick business angled investments of merlin were never going to satisfy us as nerds, they were made to make money. Europa makes rides to showcase what they can do for other investors in the industry, and to maintain their families established quality in the industry. The way the parks are ran follows a similar ideology. Of course ultimately the aim is the same; to attract guests to the park to spend money, and come back in the future, but ultimately the way about it is where a lot of the difference lies.