The verbal names and IP numbers for the traceroutes in general. It's fine to hide names that are on your LAN side of the equation but if you look at your entire traceroute output, there is not one single IP address from the start to the end, everything is X:X:X:X but in this case, some of the routers are blocking icmp requests as you can see even in my traceroute and I have all the addresses visible, you will still not be able to reach my computer using the information:
Tracing route to 1fichier.com [2a00:fb40:a:1::140]
over a maximum of 30 hops:
1 13 ms 5 ms 1 ms 2601:645:c47f:e2fd::1
2 10 ms 11 ms 10 ms 2001:558:4000:5c::1
3 11 ms 9 ms 9 ms po-303-1227-rur01.sfmission.ca.sfba.comcast.net [2001:558:82:4806::1]
4 10 ms 10 ms 11 ms ae-210-rar01.santaclara.ca.sfba.comcast.net [2001:558:80:374::1]
5 12 ms 12 ms 20 ms be-39911-cs01.sunnyvale.ca.ibone.comcast.net [2001:558:3:25c::1]
6 12 ms 16 ms 12 ms be-3102-pe02.529bryant.ca.ibone.comcast.net [2001:558:3:274::2]
7 12 ms 13 ms 12 ms 2001:559::cf2
8 * * * Request timed out.
9 * * * Request timed out.
10 * * * Request timed out.
11 * * * Request timed out.
12 * * * Request timed out.
13 * * * Request timed out.
14 * * * Request timed out.
15 * * * Request timed out.
16 * * * Request timed out.
17 * * * Request timed out.
18 * * * Request timed out.
19 160 ms 160 ms 159 ms 2001:978:2:2c::de:2
20 155 ms 152 ms 153 ms
www.1fichier.com [2a00:fb40:a:1::140]
Even hop #1 is already on my ISPs side.
There had been times when ipv6 is broken as setting up ipv4 is a given but ipv6 needs to supported by the ISP and unless you had access to the router, you wouldn't be able to setup the IPv6 or the ipv4 either. I mean what's the make and model of your router and the ONT as that would be a start. Well, the site(s) whether they mention Portuguese ISPs or not is not the issue, the issue is they have people who have more knowledge about how things like this work more than people on this site would because they have specific forums for each ISP among other things and even hardware manufacturers and that is usually where people talk about connectivity so it's more dedicated for connectivity that has existed since 1999 as their slogan is "DSLReports is the web's oldest and largest broadband and internet connectivity community. We report on ISP news, provide user connectivity diagnostic tools, ISP reviews, user-user support forums and user-ISP support forums.". This site is more for OS support than internet connectivity. The ONT is something similar to a Cable Modem or DSL Modem in that it only carries the signal and does not do any type of blocking or mapping, the router should be what you should be concerned about and this is only if you confirmed with other people like friends who use the same ISP in the same area or city that they do not have problems with 1fichier.com. If they do, then other than switching ISPs to one that works, you wouldn't be able to solve the issue without using a VPN. The other question is, is there a reason you can't use another site other than 1fichier or is it because the file(s) you want is only on 1fichier for download?