Which subd to choose for storing reports?

Question

Database

Such a problem.
Our system receives certain reports from the external, in each report a line is a certain set of fields.
Some can change and some can't. There was an attempt to start this storage on ClickHouse on ReplaceMergeTree, until there was a problem that the elements of this report tend to disappear if the operation was canceled in an external system. In ClickHouse, CollapsingMergeTree solves this issue, but doesn't solve the one that ReplaceMergeTree does.
What systems can be used for such storage, or are there such systems in ClickHouse?
There was an idea to use mongo, but we are afraid that with frequent resaving it will work very slowly.