Sorry for my reply. I am only an F-Secure user (their home solutions).
There is a discussion about subject (probably):
If your experience is also about this - did you try 'known' workaround(?):
And if a workaround is not helpful anymore - good to contact their official F-Secure Support Channel (chat as example):
Can be useful for boost up situation or as request for clarification if anything planned to be introduced against device's abilities.
Thanks Ukko, but I can´t find Protected apps option
So, if the Knowledgebase article is no longer actual (or it is not enough) - I still suggest contacting their official F-Secure Support Channels (chat as example):
at least, it should be useful for getting the proper advice.
Another suggestion is next:
I am not so experienced with Android platform and I am not sure if the proposed knowledgebase article is about general steps or specific ones (for a certain device manufacturer).
If it is about general steps - then I tried to check with my own device and there is another wording of thins:
I tried with my Nokia Android 8.1.0 device and there is settings for Battery Optimizations (Settings -- Apps and Notifications -- Advanced -- Special App Access -- Battery Optimization -- switch filters from to "all applications" as All apps -- search F-Secure solution there -- choose it and Do Not Optimize).
Maybe your device with related options too; but I am not sure if this is applied for and works against own manufacturer's "Ultra Battery" functionality. But it is possible to doublecheck.