An issue can only be fixed once it is well characterised - and seeing as this is an issue that affects only a subset of users in seemingly ill-defined circumstances, that already puts the developers at a disadvantage. You’re in the IT business, so you know very well that some bugs show only in a limited number of circumstances without an obvious cause, also the trigger might be a bug in third-party code. Moreover, all bugs are triaged, typically based on priority and impact.
Brigading Steinberg won’t help. Well-written bug reports with dump files if they are generated will help.
So far as legal action goes, you can read the advice I wrote on that topic here. Not all of that applies to you - I don’t know who your retailer was (it might not be Asknet) and you appear to have bought as a consumer, so would have consumer law protections.
It is very unlikely to be worth your while hiring a lawyer. I can only speak for the small claims rules in England and Wales, but over here, you cannot claim legal costs in a Small Claims track claim, so you would likely pay a lawyer more to litigate the case for you than you could receive in damages.
If you are done with Cubase, I’d sell your licence and move on - it’s the cheapest, lowest stress option.