Hi @Kosodrom,
looking at the stats, it looks like none of the indices grew beyond 50GB before being rolled over. The present 00005 version is just 5GB. The previous indices are: 11GB, 28GB, 44GB, 32GB.
I wonder if part of the confusion is total index size (primaries+replicas) vs just size of primaries. Rollover only triggers based on primary size. So if you want it to trigger when primary+replica=50GB, you have to set the max size to 25GB (looks like you use 1 replica).
About the ILM bootstrap problem, using data streams solves that, available since 7.9. I am not 100% up to speed on logstash compatibility with data streams though, feel free to ask in the logstash topic for that.