If you live in the US or Europe, just look on Amazon ... lots of Fujichrome including, believe it or not, Velvia 100 in the US (I thought it was banned). But the prices are silly ... or rather, they are on a par with those in Japan, i.e. high. It's a similar price to Ektachrome.
I bought two rolls of Provia 100f 35mm for €22 each (Amazon Prime, UK site) last week for delivery to Ireland. By the way, on Amazon these goods come from the "Fujifilm Store" ... where most of the items are digital cameras
FotoImpex (Berlin) had 120 size Provia a couple of weeks ago, but they were charging €19/roll, so I'm just waiting for some to come available at the "normal" EU price of around €60 for a box of five. I got my last lot (3 boxes) around 4 months ago and have been waiting for me since then ... hope to get some before December (2025 to be clear) ... you need patience in this game, it's available, occasionally.