My pre-Covid strategy to keep SEN was to buy a F RTW ticket and use it for Asia-Europe-Africa-Europe-America-Asia. Ex Japan or Korea it was in the range of 10-12.000 USD and got me where I needed to go. Such a ticket provided over 100.000 status miles for triple miles in F, enough for SEN when done inside one calendar year.
Otherwise I just used the airline which had best schedule / comfort / price for my trips.
Now such a RTW would give 1500 Points for the 5 F segments and then 200-320 Points for the 5-8 continental C flights. Not enough for SEN and also every year and not every second year.
SEN is less valuable for me now since they closed the lounge on my home airport, it is getting more difficult to get F award tickets and impossible to find two F seats for the companion award. Not sure if it makes sense to chase SEN in the future.