MariaDB instance in cloud hit 95% CPU utilisation for 30 mins
(Not yet an "Answer", but debugging help:)

High CPU almost always means a SELECT needs optimizing.  To find out which query:


Run SHOW FULL PROCESSLIST; when the naughty query is running (10:00?).  Run it a few times; hopefully, you can spot some query with a large "Time" or perhaps it is being run repeatedly.
Or us the SlowLog to find it.  Here are tips on how to get the info and present it to us here for help.


You show heavy I/O also.  That could be a query that is doing a table scan.  Again, find the query and ask for help.

Meanwhile, refresh graphs, and add one for "slow queries", if it exists.