For anyone who has similar problems...

I had problems with downloading from my local network Calibre Library directly to my Tachiyomi folders on a SD in Alita but I finally found a browser that allows to change download folder to any custom folder you want on a SD or Internal memory and also asks you every time if you want to change it. It's Opera lol.

Had problems with Firefox and Chrome. Chrome didn't detect SD card or asked me for location even if I turned that option on (bug?) and with Firefox they disabled about:config in newer versions so you cannot change anything. Really disappointed with Mozilla and Google about this.