Need optimization in query

Hi Team.

*I have a use case to get the result as follows:*

1. asin_ymm is never null.
2. If there is more than 1 entry for an asin_ymm with both null and
non-null submodelId, I should return rows with non-null submodelId only,
otherwise if there is no submodelid present for a asin_ymm, then return
that row with null submodelid.
3. Also if submodelid is null , assuming fitment_key would always be null
in the table.
4. Using that resultset, If there is more than 1 entry for an (asin_ymm
,SubmodelID) with both null and non-null fitment_key, I should return rows
with non-null fitment_key only, otherwise if there is no fitment_key
present for a (asin_ymm,submodelId), then return that row with null
fitment_key.
5. Using that resultset, i need to return those rows having maximum values
in fitment_key(ie. for eg.(out of these two 'A', 'D','1--3-4' and A',
'D','1-2-3-4-7', i should return row having A', 'D','1-2-3-4-7)

create table fitment_records(asin_ymm varchar(50), SubmodelID varchar(50),
fitment_key varchar(50));

insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('A',
null,null);
insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('B',
null,null);
insert into fitment_records(asin_ymm, SubmodelID,fitment_key ) values('C',
null,null);
insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('A',
'D','1--3-4');
insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('B',
'E','2-3-4-5');
insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('B',
'E', null);
insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('A',
'F','2-3');
insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('A',
'E', null);
insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('A',
'D', null);
insert into fitment_records(asin_ymm, SubmodelID,fitment_key) values('A',
'D','1-2-3-4-7');

output should be:

asin_ymm | submodelid | fitment_key
----------+------------+-------------
A | D | 1-2-3-4-7
A | E | null
A | F | 2-3
B | E | 2-3-4-5
C | null | null

Currently i have written these queries for this usecase. Can we
optimise it further? Considering data is in millions

create temporary view tv1 as (SELECT *
FROM fitment_records fr_1
WHERE fitment_key IS NOT NULL OR
(fitment_key IS NULL AND
NOT EXISTS (SELECT 1 FROM fitment_records fr_2
WHERE fr_2.asin_ymm = fr_1.asin_ymm AND
fr_2.SubmodelID = fr_1.SubmodelID and
fr_2.fitment_key IS NOT NULL)));

create temporary view tv2 as (select *
FROM tv1 fr_1
WHERE SubmodelID IS NOT NULL OR
(SubmodelID IS NULL AND
NOT EXISTS (SELECT 1 FROM fitment_records fr_2
WHERE fr_2.asin_ymm = fr_1.asin_ymm AND
fr_2.SubmodelID IS NOT NULL) ));

create temporary view fitment_records_with_fitment_key_size as (
select asin_ymm, SubmodelID, fitment_key,
Array_Length(string_to_array(fitment_key, '-'),1) as fitment_key_size
from tv2
where SubmodelID is not null
and fitment_key is not null
group by asin_ymm, SubmodelID, fitment_key
);

create temporary view fitment_records_with_fitment_key_max_size as (
select asin_ymm, SubmodelID, max(fitment_key_size) as max_fitment_key_size
from fitment_records_with_fitment_key_size
group by asin_ymm, SubmodelID
);

select * from tv2
except
select f2.*
from fitment_records_with_fitment_key_size frws,
fitment_records_with_fitment_key_max_size frwms,
tv2 f2
where frws.asin_ymm = frwms.asin_ymm
AND frws.SubmodelID = frwms.SubmodelID
AND frws.fitment_key_size < frwms.max_fitment_key_size
AND frws.SubmodelID = f2.SubmodelID
AND frws.asin_ymm = f2.asin_ymm
AND frws.fitment_key = f2.fitment_key;

Thanks & Regards