A sequel for the anime has already been announced.
For those who are asking:
"Where are we in the manga or the novel, so that I can continue?“
Well, first of all, this season adapted Volume 3 and 4, and with this episode, Volume 4 of the light novel has been fully adapted.
Second, there are two simultaneously running manga adaptations (don't ask why, we don't have the answer). One drawn by Nekokurage, the other by Minoji Kurata. The anime is currently ahead of the former, while the latter is only slightly ahead and aside from a fan translation that you can find if you just do a little bit of research, you won't get very far in terms of content.
Therefore, the only real option to read more of the story is to read the light novel. And if you want to continue where Season 2 ended, continue with Volume 5.
"Should I continue where the anime left off or should I start from the beginning? Would I miss out on anything if I skipped the first volumes?"
The anime follows the plot of the novel well. You wouldn't miss much overall, but since the novel is largely narrated from Maomao's POV, her thoughts and feelings aren't as well conveyed in the anime, which is compensated in the anime with scenes that Maomao can't know about. The novel also potentially explains some plot points better. It's up to you.
"Where can I read the light novel?"
For English releases, the official publishers are Square Enix (physical) and J-Novel Club (digital). So far, 14 volumes have been fully translated in English and Volume 15 is currently being translated. Every week parts of Volume 15 are pre-published and I encourage novel fans to join our prepub discussions every Friday.
Well, and if you don't want to read the novel, hopefully we will see you when the sequel comes out. The news of a date will surely be shared here as soon as we get more information.
Fast. I can fully use my 800 Mbps network while in DDL. It is usually capped at 40 or 60 Mbps. It has other downsides too like only being able to download one file at the same time or having a cooldown b/w download(which I am sure J2Downloader can fix that). I usually torrent or If I am in a hurry I just stream it from some good sites.