OK SOLVED! For anyone who face the same issue, specifically with translated filters being the target.
Relative links is the first step but you also have to add both languages for the filter in the url : /collection/nameofthecollection?filter.p.product_type=NAMEINFRENCH&filter.p.product_type=NAMEINENGLISH
For example if the filter is “Shirt”
/collection/nameofthecollection?filter.p.product_type=Chemises&filter.p.product_type=Shirts
A bit tedious but it does work!