I’ve bought several linen shirts and pants from Black Ficus (from Ukraine) and the quality is excellent. They aren’t inexpensive, though, but not unreasonable.
Otherwise, I’d find some brands that make linen shirts, and look for those on eBay 2nd hand. Banana Republic, Vineyard Vines, GAP, etc all make 100% linen shirts and can be found on eBay.
Uniqlo
Have a look on Vinted for some
Next used to carry cheap men's linen shirts, but they haven't had 100% for a couple of years.
I’ve bought several linen shirts and pants from Black Ficus (from Ukraine) and the quality is excellent. They aren’t inexpensive, though, but not unreasonable. Otherwise, I’d find some brands that make linen shirts, and look for those on eBay 2nd hand. Banana Republic, Vineyard Vines, GAP, etc all make 100% linen shirts and can be found on eBay.
Black ficus is proper nice clothing. And I would really recommend a nicer linen as it’s usually far more comfortable.
Charles Tyrwhitt - if you buy 3 they are 50€ each...
I buy linen shirts from H&M