Timber under eaves that cannot be maintained later

[kungfuu]

Hello,
I need to replace the timber under the eaves and probably the fascia boards since they won't be easily maintained in the long run as a conservatory will be in the way. I'm considering fiber cement or composite, but it's extremely difficult to find good suppliers and dimensions.

This one matches the dimensions I have underneath quite well, but will it work well?
https://www.lakkapaa.se/byggmateria...301410-onewood-natural-80x4200x15mm/17515092/

I'd appreciate tips on good outdoor "wood" solutions that will last many years without maintenance.