I have no problem paying for it, but what I miss is a clear recommendation how to get started if you have the rather common case of your own AWS Account using ElastiCache.

If I buy into the Redis Enterprise Cloud, what are it's preferred usage scenarios, how do I secure the connection properly, etc. etc. etc.

This is just shoving a buy button in my face and I have no idea how to decide if what I'm buying is actually feasible for me, for example from a compliance pov.

Not an expert, but when I researched this, I think that they run the redis in your AWS account. So it's not an external connection.

Redis Cloud Pro can run in your VPC.

Great. How? Is that recommended? What kind of user rights I need to give redis to manage that instance in my vpc? How to lock that down to the minimum without breaking it? In that configuration, what risks do I have to control for otherwise? ...

All these details should be covered by https://docs.redislabs.com/5.2/rv/how-to/creating-aws-user-r...

That's a shame. I'm trying to not use Amazon, Google or Microsoft, so this means their solution probably won't work for me. Silly really.

RedisLabs's cloud solution is running on all these clouds see: https://redislabs.com/redis-enterprise-cloud/

You don't have to pay for Redis Enterprise license, you can run it on self managed Redis too. You can view the RediSearch license https://github.com/RediSearch/RediSearch/blob/master/LICENSE

Disclaimer: I work for Redis Labs.

You can use RedisSearch on Redis Cloud Essentials with our free plan. We currently support AWS/Mumbai (ap-south-1) and we plan to gradually make it available in other regions as well.