I know it's an old thread, but have you checked the Allen Edmonds formal sneaker range? It's comfortable and made for an office setting, but not as casual as the other stuff on here.
Ah this is similar to the one Chris Evans wore in Knives out, became viral back then It again got some praise when a character in The Mandalorian wore it. A 100% cotton variant is available on Amazon.
I bought some thick wool socks from amazon, you might have some luck there.
Also, mfa often recommends these:
For me, I find any clothing with better than crappy bargain basement quality is non-existent in Romania. I find, however, I can get better items and cheaper on Amazon from Germany. Recently, I found these Amazon Escentials flannel shirts a few weeks ago and have been very impressed. While they aren't ultra thick, their quality and sizing is much better than anything in this country and only cost 15 Euros. Checking the link, Amazon says they are currently out of stock but I've also seen them on Amazon in the US and UK. I'd assume they'll come back in stock or could possibly be found in Spain or Italy.
Also, at the time I bought the flannels I sprung for for a Carhartt Detroit Duck jacket. 89 Euros and maybe one of the most amazing purchases I've ever made.
I found these amazing pants on Amazon: https://www.amazon.com/dp/B07BBNF38B/ref=cm_sw_r_other_apa_i_1wqGEbY71JDK2
The seller has some other styles too.
Sadly they did not work for me cause I'm a lady and they're built for men's hips.