I have a long list of the values in the filter list.
It takes 5 seconds until the values are displayed.
Is there any way how to optimize the displaying the filter? For example some server-side filter for only values of the current year. But it should be also able to find the older values. That could be found by the user when he would be typing.
Yes, for this reason we have a IsFilteredServerside flag in the lookup. You need to provide a filter set for the list which requires a single string value (an input from the user). Then the list is filtered server side and also paginated. It should solve your use case with looking for a long list of transactions etc.
Combining it e.g. with a sort by date descending and a corresponding index (date descending) should provide a very good performance because of the pagination.