You have to send an email for a Tildes invitation if you don’t personally know someone on there. It took me like 5 days to get the return email and it did go to spam. You can PM me if you still want an invite or go here for the site and sign up info.
You are correct about Tildes. They are very intentionally cultivating a different atmosphere and don’t want Reddit’s huddled masses. There is a subset of reddit users who fit there but it’s not the shitposting crowd.