How estimate memory usage for Prometheus

We are using Prometheus for scraping metrics and keep them for 8 hours (for longer peried we are using Victoria Metrics). I tried to find out, how much MEM should Prometheus have for current amount of series. I find out How much RAM does Prometheus 2.x need for cardinality and ingestion? with calculator. From the article, there is some points which are unclear to me:

• Number of Time Series* - it should be result of max_over_time(prometheus_tsdb_head_series[1d]) query. In my case, there is multiple results, so I sum it with sum(max_over_time(prometheus_tsdb_head_series[1d])). Is this approach right?
• Average Labels Per Time Series* - count number of key-value pairs of all labels and count average. E.g. {a="123", b="456"} is counted as 2.
• Number of Unique Label Pairs* - find uniq key-value pairs. E.g. {a="123", b="456"} and {a="123", b="abc"} equals to 2 uniq label pairs
• Average Bytes per Label Pair* (Including the =, "" and ,) - e.g. { "__name__": "up", "app_version": "0509b54", "instance": "1", "job": "event-metric-exporterd", "stack_version": "MR" }. I remove spaces and {, }. So final string is "__name__":"up","app_version":"0509b54","instance":"1","job":"event-metric-exporterd","stack_version":"MR". Then, I encode it with utf-8 and get length of string, in this case 106. I do this process for each uniq labels and count average. Is this right?
• Bytes per Sample - there is query rate(prometheus_tsdb_compaction_chunk_size_bytes_sum[1d])/rate(prometheus_tsdb_compaction_chunk_samples_sum[1d]) which again, in my case return multiple series. It take max() because it is worst case scenario.

The calculator counts:

• Cardinality Memory - how much memory Prometheus needs for various series/cardinality? Do I understand correctly?
• Ingestion Memory - memory used by Prometheus to ingest data - load and process it from targets?

Do I understand correctly Cardinality Memory and Ingestion Memory? Is my calculation process correct? Is there better way how to estimate memory for Prometheus?

Using Prometheus in docker prometheus:v2.29.1.