Building dymanic query with many laterail joins - sql

Question

I am building a dynamic query based on user-submitted conditions on user-specified fields.
I have a two tables
Visitors(id, name, email...)
and a
Trackings(id, visitor_id, field, string_value, integer_value, boolean_value, date_value)
The conditions comes in the form of an array of SQL fragments built earlier. Default filters for attributes that are hardcoded on the visitors table, and custom filters, for the values that are user-submitted and stored in an EAV schema (trackings)
Example:
Default:
{"name ILIKE 'Jack'", "(last_seen < (current_date - (7 || ' days')::interval))"}
Custom:
{"field = 'number_of_orders' > 10", "is_pro_user = true"}
A visitor can have many trackings, each one recording some custom, user-submitted data field for that visitor. But each visitor also has some default data that lies on the table itself, such as email, name or last_seen etc.
Now, users should be to ask queries such as:
Give me all the visitors for which no custom field named number_of_orders has been recored (is unknown)
Give me all visitors with the default attribute name set to Jack and for who the custom attribute total_purchase_value is greater than 1000
My attempt at solving it was using a stored procedure that dynamically concatenated a series of conditions using AND (for default data on the visitor table), and OR statements (for the custom data in the trackings table) inside a WHERE-caluse
CREATE OR REPLACE FUNCTION find_matching_visitors(app_id text, default_filters text[], custom_filters text[])
RETURNS TABLE (
id varchar
) AS
$body$
DECLARE
default_filterstring text;
custom_filterstring text;
default_filter_length integer;
custom_filter_length integer;
sql VARCHAR;
BEGIN
default_filter_length := COALESCE(array_length(default_filters, 1), 0);
custom_filter_length := COALESCE(array_length(custom_filters, 1), 0);
default_filterstring := array_to_string(default_filters, ' AND ');
custom_filterstring := array_to_string(custom_filters, ' OR ');
IF custom_filterstring = '' or custom_filterstring is null THEN
custom_filterstring := '1=1';
END IF;
IF default_filterstring = '' or default_filterstring is null THEN
default_filterstring := '1=1';
END IF;
sql := format('
SELECT v.id FROM visitors v
LEFT JOIN trackings t on v.id = t.visitor_id
WHERE v.app_id = app_id and (%s) and (%s)
group by v.id
having case when %s > 0 then count(v.id) = %s else true end
', custom_filterstring, default_filterstring, custom_filter_length, custom_filter_length);
RETURN QUERY EXECUTE sql;
END;
$body$
LANGUAGE 'plpgsql';
This works great, but AFAIK there is not way to express the unknown filter for a custom attribute. In that it would require using a left outer join, or a not exists subquery with access to the outer scope.
I am now looking at alternative ways to accomplish the same as above, but also support this kind of query. I am thinking something like the below, using a series of lateral joins for each condition, but this seems like it won't perform very well as soon as there is more than 1-2 conditions/joins.
select v.id, v.name from visitors v
inner join lateral ( <-- custom fields
select * from trackings t
where field = 'admin'
) as t1 on t1.visitor_id = v.id
inner join lateral (
select * from trackings t
where field = 'users_created'
) as t2 on t2.visitor_id = v.id
inner join lateral (
select * from trackings t
where field = 'teams_created' and integer_value > 0
) as t3 on t3.visitor_id = v.id
where v.app_id = 'ASnYW1-RgCl0I' and (v.type = 'lead' or v.type = 'user')
and name ILIKE 'mads' and email is not null // <-- default fields
Any suggestions?